Pmc.ncbi.nlm.nih.gov - SEO Checker

Sign up for free! PDF Export
Overview of the SEO Check
Meta information
79% 
Page quality
55% 
Page structure
100% 
Link structure
97% 
Server
100% 
External factors
100% 
SEO Score
Response time
0.24 s
File size
62.80 kB
Words
388
Media files
12
Number of links
13 internal / 21 external

Task list of SEO Improvements

Meta specifications

Title
(Critically important)
PMC Home
The page title is too short. (103 pixels of 580 max pixel length) Optimize title
There are no duplicate words in the title
Meta description
(Critically important)
PMC is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).
The length of the meta description is perfect. (982 pixels out of 1000 max pixel length)
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)
This page is hosted on a subdomain. Use a top level domain for better SEO results.
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
HandheldFriendlyTrue
MobileOptimized320
viewportwidth=device-width, initial-scale=1.0
ncbi_pagehome
ncbi_oppage_view
robotsINDEX,FOLLOW,NOARCHIVE
descriptionPMC is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).
og:titlePubMed Central (PMC)
og:typewebsite
og:site_namePubMed Central (PMC)
og:descriptionPMC is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).
og:urlhttps://pmc.ncbi.nlm.nih.gov/
og:imagehttps://cdn.ncbi.nlm.nih.gov/pmc/cms/images/pmc-card-share.jpg?_=0
msapplication-config/static/img/favicons/browserconfig.xml
theme-color#ffffff
ncbi_appcloudpmc-viewer
ncbi_dbpmc
ncbi_phidFB70A6F282DE6C4310A6F2001BB3C1D5.m_5
ncbi_pinger_stat_urlhttps://pmc.ncbi.nlm.nih.gov/stat
ncbi_pdidhome
langen
twitter:cardsummary_large_image
twitter:site@ncbi
X-UA-CompatibleIE=edge
charsetUTF-8

Automatically check pmc.ncbi.nlm.nih.gov including all subpages at once!

Try for free
Guaranteed free of charge during trial period.

Page quality

Content
(Critically important)
Words from the H1 heading are not used in the page content.
There are only 388 words on this page. Good pages should have about 800 words of useful content.
29.1% of the text are stop words.
The page contains a listing, which indicates a good text layout.
5 paragraphs were found on this page.
No placeholders texts or images were found.
There are no duplicates on the site.
The average number of words per sentence of 18 words is good.
Frames
(Critically important)
This page does not use a frameset.
Mobile optimization
(Somewhat important)
A viewport "width=device-width, initial-scale=1.0" is provided.
At least one Apple touch icon is specified.
Bold and strong tags
(Somewhat important)
The usage of strong and bold tags is perfect. We recommend the use of up to 8 tags for this page.
Image SEO
(Somewhat important)
7 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
/static/img/us_flag.svgNo alt attribute provided
...c/img/ncbi-logos/nih-nlm-ncbi--white.svg NCBI home page
/static/img/usa-icons/close.svgClose
data:[...] Base64Search
/static/img/usa-icons-bg/search--white.svgSearch
/static/img/icon-about.pngNo alt attribute provided
/static/img/icon-guide.pngNo alt attribute provided
/static/img/icon-collections.pngNo alt attribute provided
/static/img/icon-authors.pngNo alt attribute provided
/static/img/icon-publishers.pngNo alt attribute provided
/static/img/icon-developers.pngNo alt attribute provided
...nih.gov/pmc/cms/images/trybetasearch.jpgScreenshot showing the link to try the Beta Search

Page structure

H1 heading
(Critically important)
PubMed Central (PMC) Home Page
The H1 heading is perfect.
Headings
(Important)
The heading structure is perfect.

Heading structure

Heading levelContent
H1 PubMed Central (PMC) Home Page
H2 About PMC
H2 User Guide
H2 Collections
H2 For Authors
H2 For Publishers
H2 For Developers
H2 10.9 million articles are archived in PMC.
H2 New in PMC
H2 Updated Full-Text Search Preview Now Available
H3 2976
H3 Full Participation Journals
H3 264
H3 NIH Portfolio Journals
H3 43
H3 Selective Deposit Programs
H3 PubMed Central's Updated Full-Text Search Preview Now Available
H3 Preview of Upcoming Changes to PMC's eFetch Output
There are 1 links with a trivial anchor text.
The number of internal links is ok.
Every linktext is unique.
None of the anchor texts is too long.
All internal links are not using dynamic parameters.
There are 21 external links on this page.

Found links on this page

LinkAttributesAnchor text
https://pmc.ncbi.nlm.nih.gov/Anchor Skip to main content
https://www.ncbi.nlm.nih.gov/External Subdomain IMG-ALT NCBI home page
https://pmc.ncbi.nlm.nih.gov/A-TITLE Home
https://www.ncbi.nlm.nih.gov/p...External Subdomain Advanced
/journals/Journal List
/about/intro/About PMC
/about/userguide/User Guide
/about/collections/Collections
/about/submission-methods/For Authors
/pub/pubinfo/For Publishers
/tools/developers/For Developers
/about/new-in-pmc/PubMed Central's Updated Full-Text Search Preview Now Available
/about/new-in-pmc/Preview of Upcoming Changes to PMC's eFetch Output
/about/new-in-pmc/Updated Full-Text Search Preview Now Available
/about/new-in-pmc/Trivial anchor text
Read More
https://twitter.com/ncbiNew window External NCBI on X (formerly known as Twitter)
https://www.facebook.com/ncbi.nlmNew window External Subdomain NCBI on Facebook
https://www.linkedin.com/compa...New window External Subdomain NCBI on LinkedIn
https://github.com/ncbiNew window External NCBI on GitHub
https://ncbiinsights.ncbi.nlm....New window External Subdomain NCBI RSS feed
https://twitter.com/nlm_nihNew window External NLM on X (formerly known as Twitter)
https://www.facebook.com/natio...New window External Subdomain NLM on Facebook
https://www.youtube.com/user/N...New window External Subdomain NLM on YouTube
https://www.google.com/maps/pl...New window External Subdomain National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894
https://www.nlm.nih.gov/web_po...External Subdomain Web Policies
https://www.nih.gov/institutes...External Subdomain FOIA
https://www.hhs.gov/vulnerabil...New window External Subdomain HHS Vulnerability Disclosure
https://support.nlm.nih.gov/External Subdomain Help
https://www.nlm.nih.gov/access...External Subdomain Accessibility
https://www.nlm.nih.gov/career...External Subdomain Careers
https://www.nlm.nih.gov/External Subdomain NLM
https://www.nih.gov/External Subdomain NIH
https://www.hhs.gov/New window External Subdomain HHS
https://www.usa.gov/New window External Subdomain USA.gov

Server configuration

HTTP redirects
(Critically important)
This page redirects to "https://pmc.ncbi.nlm.nih.gov/"
HTTP header
(Important)
No X-Powered HTTP header is sent.
The web server transmits the web page (HTML) in compressed form.
Performance
(Somewhat important)
The page response time is excellent with 0.24 seconds.
The file size of the HTML document is fine (63 kB).

HTTP Response Header

NameValue
dateWed, 21 May 2025 14:52:07 GMT
serveristio-envoy
strict-transport-securitymax-age=31536000; includeSubDomains; preload
content-typetext/html; charset=utf-8
varyAccept-Encoding
x-frame-optionsDENY
x-content-type-optionsnosniff
referrer-policysame-origin
cross-origin-opener-policysame-origin
content-encodinggzip
x-envoy-upstream-service-time99
set-cookie115 Characters
x-ua-compatibleIE=Edge
x-xss-protection1; mode=block
via1.1 google
alt-svcclear
statuscode200
http_versionHTTP/2

External factors

This page is referenced by wikipedia.
This website has excellent links from other websites.
This page has backlinks from 756 referring domains.
This page has 4,622 backlinks.
This page has backlinks from 505 different ip addresses.

Links from Wikipedia

You can find more links using Wikipedia search

Robots.txt

User-agent: *
Crawl-delay: 1
Allow: /$
Allow: /about/
Allow: /articles/
Allow: /sitemap/
Allow: /tools/
Allow: /pub/
Allow: /api/
Disallow: /

Sitemap: https://pmc.ncbi.nlm.nih.gov/sitemap/

Similar sites

Search preview

pmc.ncbi.nlm.nih.gov
PMC Home
PMC is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).

Most important keywords

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

KeywordResultRecheck
PMC91%Check
Search PMC68%Check
NIH63%Check
NLM59%Check
Full-Text54%Check
Journal54%Check
PubMed54%Check
Central54%Check
PubMed Central54%Check
Full-Text Archive54%Check
Show more keywords and terms

Automatically check pmc.ncbi.nlm.nih.gov including all subpages at once!

Try for free
Guaranteed free of charge during trial period.

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.

Contact | Privacy

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