Pnas.org - SEO Checker

Overview of the SEO Check
Meta information
80% 
Page quality
79% 
Page structure
62% 
Link structure
42% 
Server
56% 
External factors
100% 
SEO Score
Response time
0.38 s
File size
108.70 kB
Words
815
Media files
19
Number of links
164 internal / 30 external

Task list of SEO Improvements

Meta specifications

Title
(Critically important)
PNAS
The page title is too short. (56 pixels of 580 max pixel length) Optimize title
The page title is only one word.
There are no duplicate words in the title
Meta description
(Critically important)
The meta description is missing.
Crawlability
(Critically important)
There are no problems in accessing the website.
Canonical URL
(Important)
No canonical link is specified.
Language
(Somewhat important)
Language detected in text: en
Language defined in HTML: en
Server location: United States of America
The following language is defined by HTML: en
Alternate/Hreflang Links
(Somewhat important)
There are no alternate links specified on this page.
Other meta tags
(Somewhat important)
There is no rel next meta tag on this page.
There is no rel prev meta tag on this page.
Domain
(Somewhat important)
The domain is no subdomain.
The domain length is good.
The domain does not contain non-latin characters.
Page URL
(Somewhat important)
No parameters were found in the URL.
No session ID was found in the URL.
The URL does not have too many subdirectories.
Charset encoding
(Somewhat important)
The charset encoding (UTF-8) is set correctly.
Doctype
(Nice to have)
The doctype HTML 5 is set correctly.
The doctype is placed at first in the HTML code.
Favicon
(Nice to have)
The favicon is linked correctly.

Meta tags

NameValue
viewportinitial-scale=1, maximum-scale=1, width=device-width, user-scalable=yes
GeneratorDrupal 7 (http://drupal.org)
langen
Content-Typetext/html; charset=utf-8

Test up to 1.000 webpages of pnas.org with our free plan!

Sign Up Free
No trial. It's just free!

Page quality

Content
(Critically important)
This page contains 815 words. That's ok.
19.6% of the text are stop words.
The page contains a listing, which indicates a good text layout.
11 paragraphs were found on this page.
The text content is perfect.
No placeholders texts or images were found.
There are no duplicates on the site.
The average number of words per sentence of 20.64 words is good.
Frames
(Critically important)
This page does not use a frameset.
Mobile optimization
(Somewhat important)
No Apple touch icon is specified.
This page loads 15 JavaScript files. This may affect the load time negatively.
A viewport "initial-scale=1, maximum-scale=1, width=device-width, user-scalable=yes" is provided.
Bold and strong tags
(Somewhat important)
The usage of strong and bold tags is perfect. We recommend the use of up to 16 tags for this page.
Image SEO
(Somewhat important)
3 images have no alt attribute. The content of alt attributes is used by search engines.
Social Networks
(Nice to have)
There are only a few social sharing widgets on the page. Make your website popular in social networks with social sharing widgets.
Additional markup
(Nice to have)
No additional page markup was found.
HTTPS
(Somewhat important)
This website uses HTTPS to protect privacy and integrity of the exchanged data.
All included files are also transferred via HTTPS.

Media list

URLAlt attributeTitle
...fault/files/logo-pnas-white-header2x.pngHome
...fault/files/logo-pnas-white-header2x.pngHome
...0.png?itok=ulb6b7c6&timestamp=1609264919No alt attribute provided
...r.png?itok=UeiFuqHA&timestamp=1609942111Volume 118, Issue 1: View articles in the latest issue of PNAS.
...l.png?itok=5ssUAEAQ&timestamp=1532526780Click here to view selections in the latest issue of PNAS.
...1.jpg?itok=mejZP6Kq&timestamp=1609942482Latest in Earth, Atmospheric, and Planetary Sciences: The Pine Island and Thwaites Glaciers have undergone rapid acceleration, thinning, and grounding line retreat leading to enhanced instability. Click to read more. Image credit: Stef Lhermitte.
...tem/fm-nf-21-01-08-220.png?itok=kRKOO7LXWinding paved road
...item/fm-o-21-01-07-220.png?itok=8ng_bt8AScientist looking at an electronic tablet
...d-item/fm-nf-12-17-220.jpg?itok=GAXJLGOyInsect with white and yellow wings
...-item/pitn-1-12-14-220.jpg?itok=4RoTu8TCRats
...-item/pitn-2-12-14-220.jpg?itok=rKKIndQ1No alt attribute provided
...-item/pitn-3-12-14-220.jpg?itok=2Zv_UQcQAmundsen Sea Embayment viewed from the Copernicus Sentinel-2 satellite.
...nas/118/1.cover-source.jpg?itok=QAYo-5KtProceedings of the National Academy of Sciences: 118 (1)
...podcast-2021-01-04-220.png?itok=7WJRcWOHWhite and blue bird
...ed-item/profile-76-220.jpg?itok=KczEJaCKJoel D. Blum
...ntrib/panels_ajax_tab/images/loading.gifLoadingLoading
/sites/default/files/pnas_2x.pngSite Logo
...ent_types/images/logo_small_hw_white.pngPowered by HighWire
...dvanced-pages/logo-nas-white-footer1.pngNo alt attribute provided

Page structure

H1 heading
(Critically important)
There is no H1 heading specified.
Headings
(Important)
Some headings occur twice on the page.
The structure of headings is missing one or more levels. Do not skip heading levels.

Heading structure

Heading levelContent
H2 Main menu
H2 User menu
H2 Search
H2 New Research In
H2 Front Matter
H2 In the News
H2 Sign up for Article Alerts
H2 Science Sessions Podcasts
H2 Featured Profile
H2 Latest Articles
H2 Articles
H2 PNAS Portals
H2 Information
H3 Physical Sciences
H3 Social Sciences
H3 Biological Sciences
H4 Featured Portals
H4 Articles by Topic
H4 Featured Portals Duplicate text
H4 Articles by Topic Duplicate text
H4 Featured Portals Duplicate text
H4 Articles by Topic Duplicate text
Some internal link anchor texts are too long.
Some internal links have dynamic parameters. All internal URLs, which are not marked as nofollow, should not contain dynamic parameters.
Some anchor texts are used more than once.
2 links don't have an anchor text.
The number of internal links is ok.
There are too many external links (30) on this page.
LinkAttributesAnchor text
https://www.pnas.org/Anchor Skip to main content
https://www.pnascentral.org/cg...New window External Submit
https://www.pnas.org/page/aboutAbout
/page/about/editorial-boardEditorial Board
/page/about/staff-directoryPNAS Staff
/page/about/faqFAQ
/page/about/accessibilityAccessibility Statement
/page/about/rights-permissionsRights and Permissions
/content/site-mapNew window Site Map
/page/about/staff-directoryContact
https://blog.pnas.org/New window External Subdomain Journal Club
/page/subscriptions/subscribersSubscribe
/page/subscriptions/ratesSubscription Rates
/page/subscriptions/subs-faqSubscriptions FAQ
/page/subscriptions/open-accessOpen Access
/page/subscriptions/recommend-...Recommend PNAS to Your Librarian
/user/login?destination=/frontLog in
https://www.pnas.org/cartMy Cart
https://www.pnas.org/Home
/content/currentArticles
/content/currentCurrent
/content/early/recentLatest Articles
/page/about/special-featuresSpecial Features
/page/about/colloquiaColloquia
/page/about/collected-papersCollected Articles
http://classics.pnas.org/New window External Subdomain PNAS Classics
/content/by/yearList of Issues
/portal/front-matterFront Matter
/page/about/pressNews
/page/about/pressFor the Press
https://www.pnas.org/twipThis Week In PNAS
/page/media/newsPNAS in the News
/page/media/podcastsPodcasts
https://www.pnas.org/authorsAuthors
https://www.pnas.org/authorsInformation for Authors
/authors/editorial-and-journal...Editorial and Journal Policies
/authors/submitting-your-manus...Submission Procedures
/authors/fees-and-licensesFees and Licenses
https://www.pnascentral.org/cg...New window External Text duplicate Submit
https://www.pnas.org/page/aboutText duplicate About
/page/about/editorial-boardText duplicate Editorial Board
/page/about/staff-directoryText duplicate PNAS Staff
/page/about/faqText duplicate FAQ
/page/about/accessibilityText duplicate Accessibility Statement
/page/about/rights-permissionsText duplicate Rights and Permissions
/content/site-mapNew window Text duplicate Site Map
/page/about/staff-directoryText duplicate Contact
https://blog.pnas.org/New window External Subdomain Text duplicate Journal Club
/page/subscriptions/subscribersText duplicate Subscribe
/page/subscriptions/ratesText duplicate Subscription Rates
/page/subscriptions/subs-faqText duplicate Subscriptions FAQ
/page/subscriptions/open-accessText duplicate Open Access
/page/subscriptions/recommend-...Text duplicate Recommend PNAS to Your Librarian
/user/login?destination=/frontText duplicate Log in
https://www.pnas.org/cartText duplicate My Cart
https://www.pnas.org/searchAdvanced search
A-TITLE Advanced search
https://www.pnas.org/Text duplicate IMG-ALT Home
A-TITLE Home
https://www.pnas.org/Text duplicate IMG-ALT Home
A-TITLE Home
https://www.pnas.org/searchAdvanced Search
https://www.pnas.org/Text duplicate Home
/content/currentText duplicate Articles
/content/currentText duplicate Current
/content/early/recentText duplicate Latest Articles
/page/about/special-featuresText duplicate Special Features
/page/about/colloquiaText duplicate Colloquia
/page/about/collected-papersText duplicate Collected Articles
http://classics.pnas.org/New window External Subdomain Text duplicate PNAS Classics
/content/by/yearText duplicate List of Issues
/portal/front-matterText duplicate Front Matter
/page/about/pressText duplicate News
/page/about/pressText duplicate For the Press
https://www.pnas.org/twipText duplicate This Week In PNAS
/page/media/newsText duplicate PNAS in the News
/page/media/podcastsText duplicate Podcasts
https://www.pnas.org/authorsText duplicate Authors
https://www.pnas.org/authorsText duplicate Information for Authors
/authors/editorial-and-journal...Text duplicate Editorial and Journal Policies
/authors/submitting-your-manus...Text duplicate Submission Procedures
/authors/fees-and-licensesText duplicate Fees and Licenses
http://physics.pnas.org/External Subdomain Physics
http://chemistry.pnas.org/External Subdomain Chemistry
http://sustainability.pnas.org/External Subdomain Sustainability Science
/content/by/section/Applied Ma...Applied Mathematics
/content/by/section/Applied Ph...Applied Physical Sciences
/content/by/section/AstronomyAstronomy
/content/by/section/Computer S...Computer Sciences
/content/by/section/Earth, Atm...Earth, Atmospheric, and Planetary Sciences
/content/by/section/EngineeringEngineering
/content/by/section/Environmen...Environmental Sciences
/content/by/section/MathematicsMathematics
/content/by/section/StatisticsStatistics
http://anthropology.pnas.org/External Subdomain Anthropology
http://sustainability.pnas.org/External Subdomain Text duplicate Sustainability Science
/content/by/section/Economic S...Economic Sciences
/content/by/section/Environmen...Text duplicate Environmental Sciences
/content/by/section/Political ...Political Sciences
/content/by/section/Psychologi...Psychological and Cognitive Sciences
/content/by/section/Social Sci...Social Sciences
http://sustainability.pnas.org/External Subdomain Text duplicate Sustainability Science
/content/by/section/Agricultur...Agricultural Sciences
/portal/anthropologyText duplicate Anthropology
/content/by/section/Applied Bi...Applied Biological Sciences
/content/by/section/BiochemistryBiochemistry
/content/by/section/Biophysics...Biophysics and Computational Biology
/content/by/section/Cell BiologyCell Biology
/content/by/section/Developmen...Developmental Biology
/content/by/section/EcologyEcology
/content/by/section/Environmen...Text duplicate Environmental Sciences
/content/by/section/EvolutionEvolution
/content/by/section/GeneticsGenetics
/content/by/section/Immunology...Immunology and Inflammation
/content/by/section/Medical Sc...Medical Sciences
/content/by/section/MicrobiologyMicrobiology
/content/by/section/NeuroscienceNeuroscience
/content/by/section/PharmacologyPharmacology
/content/by/section/PhysiologyPhysiology
/content/by/section/Plant BiologyPlant Biology
/content/by/section/Population...Population Biology
/content/by/section/Psychologi...Text duplicate Psychological and Cognitive Sciences
/content/by/section/Sustainabi...Text duplicate Sustainability Science
/content/by/section/Systems Bi...Systems Biology
/page/coronavirusPNAS coronavirus papers
https://www.pnas.org/page/updatesAnchor learn more about our response to COVID-19
/page/toptenstories/2020No Text
/page/toptenstories/2020PNAS celebrates the Top 10 articles of 2020! Click to read more.
/content/118/1IMG-ALT Volume 118, Issue 1: View articles in the latest issue of PNAS.
/content/118/1Text duplicate Volume 118, Issue 1: View articles in the latest issue of PNAS.
https://www.pnas.org/twipIMG-ALT Click here to view selections in the latest issue of PNAS.
https://www.pnas.org/twipText duplicate Click here to view selections in the latest issue of PNAS.
/content/117/40/24735IMG-ALT Latest in Earth, Atmospheric, and Planetary Sciences: The Pine Island and Thwaites Glaciers have undergone rapid acceleration, thinning, and grounding line r...
/content/117/40/24735Text duplicate Latest in Earth, Atmospheric, and Planetary Sciences: The Pine Island and Thwaites Glaciers have undergone rapid acceleration, thinning, and grounding line r...
/content/118/3/e2024425118IMG-ALT Winding paved road
/content/118/3/e2024425118News Feature: Realizing the roads of the future
/content/118/3/e2025207118New window IMG-ALT Scientist looking at an electronic tablet
/content/118/3/e2025207118New window Opinion: Standardizing gene product nomenclature—a call to action
/content/early/2020/12/16/2018...New window IMG-ALT Insect with white and yellow wings
/content/early/2020/12/16/2018...New window News Feature: To understand the plight of insects, entomologists look to the past
http://frontmatter.pnas.org/External Subdomain All Front Matter
/content/117/38/23942IMG-ALT Rats
/content/117/38/23942Protecting against spaceflight-induced muscle and bone loss
/content/117/35/21162No Text
/content/117/35/21162Membrane-assisted radiant cooling
/content/117/40/24735IMG-ALT Amundsen Sea Embayment viewed from the Copernicus Sentinel-2 satellite.
/content/117/40/24735Antarctic ice shelf damage and instability
/page/media/newsAll News
/content/118/1IMG-ALT Proceedings of the National Academy of Sciences: 118 (1)
/content/118/1.tocCurrent Issue
https://www.pnascentral.org/cg...External Text duplicate Submit
https://traffic.libsyn.com/sec...New window External Subdomain IMG-ALT White and blue bird
https://traffic.libsyn.com/sec...New window External Subdomain Hazards of ozone pollution to birds
https://traffic.libsyn.com/sec...New window External Subdomain Listen
http://feeds.feedburner.com/pn...New window External Subdomain Past Podcasts
https://itunes.apple.com/us/po...New window External Subdomain Text duplicate Subscribe
/content/117/48/30000IMG-ALT Joel D. Blum
/content/117/48/30000Featured Profile
/content/early/2020/12/16/2016...Satellites can reveal global extent of forced labor in the world’s fishing fleet
/content/early/2020/12/16/2020...Bioavailable soil Pb minimized by in situ transformation to plumbojarosite
/content/early/2020/12/14/2013...A modern scleractinian coral with a two-component calcite–aragonite skeleton
/content/early/2020/04/17/1912...A scientific theory of gist communication and misinformation resistance, with implications for health, education, and policy
/content/early/recentView more published ahead of print articles
/panels_ajax_tab/jnl_pnas_most...Nofollow No Text
/panels_ajax_tab/jnl_pnas_most...Nofollow No Text
/content/117/51/32293Face masks considerably reduce COVID-19 cases in Germany
/content/117/46/28859Virulence mismatches in index hosts shape the outcomes of cross-species transmission
/content/117/47/29246Opinion: To stop the next pandemic, we need to unravel the origins of COVID-19
/content/117/51/32197The plasticity of well-being: A training-based framework for the cultivation of human flourishing
/content/117/48/30071Understanding the role of individual units in a deep neural network
/articles/most-readMore...
A-TITLE More...
https://www.pnas.org/IMG-ALT Site Logo
http://home.highwire.org/New window External Subdomain IMG-ALT Powered by HighWire
https://www.pnascentral.org/cg...New window External Submit Manuscript
https://twitter.com/PNASNewsNew window External Twitter
https://www.facebook.com/pages...New window External Facebook
/page/about/rssRSS Feeds
https://www.pnas.org/alertsEmail Alerts
/content/currentText duplicate Current Issue
/content/early/recentText duplicate Latest Articles
/content/by/yearArchive
http://anthropology.pnas.org/External Subdomain Text duplicate Anthropology
http://chemistry.pnas.org/External Subdomain Text duplicate Chemistry
http://pnas100th.org/External Classics
http://frontmatter.pnas.org/New window External Subdomain Text duplicate Front Matter
http://physics.pnas.org/External Subdomain Text duplicate Physics
http://sustainability.pnas.org/External Subdomain Text duplicate Sustainability Science
http://teachingresources.pnas....New window External Subdomain Teaching Resources
/page/authors/authorsText duplicate Authors
/page/about/editorial-boardText duplicate Editorial Board
/page/reviewersReviewers
https://www.pnas.org/librariansLibrarians
/page/about/pressPress
/content/site-mapNew window Text duplicate Site Map
https://www.pnas.org/page/updatesPNAS Updates
https://www.pnas.org/feedbackFeedback
/page/authors/termsPrivacy/Legal

Server configuration

HTTP redirects
(Critically important)
This page redirects to "https://www.pnas.org/"
HTTP header
(Important)
No X-Powered HTTP header is sent.
This page uses GZip for compressed data transmission.
Performance
(Somewhat important)
This page loads 10 CSS files. This may affect the page load time negatively.
This page loads 15 JavaScript files. This may affect the load time negatively.
The page response time is excellent with 0.38 seconds.
The file size of the HTML document is fine (109 kB).

HTTP Response Header

NameValue
dateSun, 10 Jan 2021 21:35:24 GMT
content-typetext/html; charset=utf-8
transfer-encodingchunked
connectionkeep-alive
set-cookie139 Characters
age0
cache-controlpublic, max-age=900, must-revalidate, proxy-revalidate, pre-check=0, post-check=0
cf-railgun046e42e817 9.24 0.121942 0030 e6be
content-languageen
etagW/"1610314227-0"
expiresSun, 19 Nov 1978 05:00:00 GMT
last-modifiedSun, 10 Jan 2021 21:30:27 GMT
pragmano-cache
varyCookie,Accept-Encoding
via1.1 varnish
x-content-type-optionsnosniff
x-drupal-cacheHIT
x-frame-optionsSAMEORIGIN
x-generatorDrupal 7 (http://drupal.org)
x-highwire-sitecodepnas
x-highwire-smart-codepnas_production
x-varnish1075606575
x-varnish-cache
x-varnish-ttl
cf-cache-statusDYNAMIC
cf-request-id078fd2bc590000bee7b3acb000000001
expect-ctmax-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
servercloudflare
cf-ray60f9870d5ffcbee7-FRA
content-encodinggzip
statuscode200
http_versionHTTP/1.1

External factors

Blacklists
(Critically important)
This website is not classified "for adult only".
This website is not listed on the Shallalist.
This page is referenced by wikipedia.
This website has excellent links from other websites.
This page has backlinks from 128,842 referring domains.
This page has 7,723,025 backlinks.
This page has backlinks from 82,191 different ip addresses.
Facebook popularity
(Somewhat important)
This page has social activity like shares, comments or likes on facebook.
Listed on Webwiki
(Nice to have)
This website is listed on Webwiki.

Robots.txt

#
# robots.txt
#
# This file is to prevent the crawling and indexing of certain parts
# of your site by web crawlers and spiders run by sites like Yahoo!
# and Google. By telling these "robots" where not to go on your site,
# you save bandwidth and server resources.
#
# This file will be ignored unless it is at the root of your host:
# Used:    http://example.com/robots.txt
# Ignored: http://example.com/site/robots.txt
#
# For more information about the robots.txt standard, see:
# http://www.robotstxt.org/robotstxt.html

User-agent: *
Crawl-delay: 10
# CSS, JS, Images
Allow: /misc/*.css$
Allow: /misc/*.css?
Allow: /misc/*.js$
Allow: /misc/*.js?
Allow: /misc/*.gif
Allow: /misc/*.jpg
Allow: /misc/*.jpeg
Allow: /misc/*.png
Allow: /modules/*.css$
Allow: /modules/*.css?
Allow: /modules/*.js$
Allow: /modules/*.js?
Allow: /modules/*.gif
Allow: /modules/*.jpg
Allow: /modules/*.jpeg
Allow: /modules/*.png
Allow: /profiles/*.css$
Allow: /profiles/*.css?
Allow: /profiles/*.js$
Allow: /profiles/*.js?
Allow: /profiles/*.gif
Allow: /profiles/*.jpg
Allow: /profiles/*.jpeg
Allow: /profiles/*.png
Allow: /themes/*.css$
Allow: /themes/*.css?
Allow: /themes/*.js$
Allow: /themes/*.js?
Allow: /themes/*.gif
Allow: /themes/*.jpg
Allow: /themes/*.jpeg
Allow: /themes/*.png
# Directories
Disallow: /includes/
Disallow: /misc/
Disallow: /modules/
Disallow: /profiles/
Disallow: /scripts/
Disallow: /themes/
# Files
Disallow: /CHANGELOG.txt
Disallow: /cron.php
Disallow: /INSTALL.mysql.txt
Disallow: /INSTALL.pgsql.txt
Disallow: /INSTALL.sqlite.txt
Disallow: /install.php
Disallow: /INSTALL.txt
Disallow: /LICENSE.txt
Disallow: /MAINTAINERS.txt
Disallow: /update.php
Disallow: /UPGRADE.txt
Disallow: /xmlrpc.php
# Paths (clean URLs)
Disallow: /admin/
Disallow: /comment/reply/
Disallow: /filter/tips/
Disallow: /node/add/
Disallow: /search/
Disallow: /user/register/
Disallow: /user/password/
Disallow: /user/login/
Disallow: /user/logout/
# Paths (no clean URLs)
Disallow: /?q=admin/
Disallow: /?q=comment/reply/
Disallow: /?q=filter/tips/
Disallow: /?q=node/add/
Disallow: /?q=search/
Disallow: /?q=user/password/
Disallow: /?q=user/register/
Disallow: /?q=user/login/
Disallow: /?q=user/logout/
# RDF resources
Disallow: /Entity/
Disallow: /external-ref?access_num=*
Disallow: /lookup*
Disallow: *panels_ajax_tab*
Disallow: /highwire/
Disallow: *ijkey*
Disallow: /user/logout?*
Disallow: /user/login?*

Facebook popularity

Shares / Likes / Comments
4,993

Only the data for the given URL is shown. We cannot determine the social actions for a linked fan page.

Search preview

www.pnas.org
PNAS

Most important keywords

Following keywords were found. You can check the keyword optimization of this page for each keyword.

KeywordResultRecheck
PNAS65%Check
Latest Articles44%Check
Articles44%Check
Sciences44%Check
Featured44%Check
Physical Sciences43%Check
Search43%Check
menu43%Check
Biological Sciences43%Check
Portals43%Check

Test up to 1.000 webpages of pnas.org with our free plan!

Sign Up Free
No trial. It's just free!

Cookie Policy

We use cookies to make our site work and also for analytics and advertising purposes. You can enable or disable optional cookies as desired. See the following links for more information.

We need these so the site can function properly

So we can better understand how visitors use our website

So we can serve you tailored ads and promotions