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United States National Library of Medicine National Institutes of Health

Fact Sheet

MEDLINE® (Medical Literature Analysis and Retrieval System Online) is the U.S. National Library of Medicine's® (NLM) premier bibliographic database that contains over 16 million references to journal articles in life sciences with a concentration on biomedicine. A distinctive feature of MEDLINE is that the records are indexed with NLM's Medical Subject Headings (MeSH®).

The great majority of journals are selected for MEDLINE based on the recommendation of the Literature Selection Technical Review Committee (LSTRC), an NIH-chartered advisory committee of external experts analogous to the committees that review NIH grant applications. Some additional journals and newsletters are selected based on NLM-initiated reviews, e.g., history of medicine, health services research, AIDS, toxicology and environmental health, molecular biology, and complementary medicine, that are special priorities for NLM or other NIH components. These reviews generally also involve consultation with an array of NIH and outside experts or, in some cases, external organizations with which NLM has special collaborative arrangements.

MEDLINE is the primary component of PubMed®, part of the Entrez series of databases provided by NLM's National Center for Biotechnology Information (NCBI). MEDLINE may also be searched via the NLM Gateway.

Time coverage: generally 1949 to the present, with some older material.

Source: Currently, citations from approximately 5,200 worldwide journals in 37 languages; 60 languages for older journals. Citations for MEDLINE are created by the NLM, international partners, and collaborating organizations.

Updates: Since 2005, between 2,000-4,000 completed references are added each day Tuesday through Saturday; over 670,000 total added in 2007. Updates are suspended for several weeks during November and December as NLM makes the transition to a new year of Medical Subject Headings (MeSH) vocabulary used to index the articles.

Broad subject coverage: The subject scope of MEDLINE is biomedicine and health, broadly defined to encompass those areas of the life sciences, behavioral sciences, chemical sciences, and bioengineering needed by health professionals and others engaged in basic research and clinical care, public health, health policy development, or related educational activities. MEDLINE also covers life sciences vital to biomedical practitioners, researchers, and educators, including aspects of biology, environmental science, marine biology, plant and animal science as well as biophysics and chemistry. Increased coverage of life sciences began in 2000.

The majority of the publications covered in MEDLINE are scholarly journals; a small number of newspapers, magazines, and newsletters considered useful to particular segments of NLM's broad user community are also included. For citations added during 2000-2005: about 47% are for cited articles published in the U.S., about 90% are published in English, and about 79% have English abstracts written by authors of the articles.

Availability: MEDLINE is the primary component of PubMed (; a link to PubMed is found on the NLM home page at The result of a MEDLINE/PubMed search is a list of citations (including authors, title, source, and often an abstract) to journal articles and an indication of free electronic full-text availability. Searching is free of charge and does not require registration. MEDLINE in PubMed may also be searched using the NLM Gateway, a single Web interface that searches multiple NLM retrieval systems.

A growing number of MEDLINE citations contain a link to the free full text of the article archived in PubMed Central® or to other sites. You can also link from many MEDLINE references to the Web site of the publisher or other full text provider to request or view the full article, depending upon the publisher's access requirements. For articles not freely available on the web, the "Loansome Doc®" feature in PubMed provides an easy way to place an electronic order through the National Network of Libraries of Medicine® (NN/LM®) for the full-text copy of an article cited in MEDLINE. Registration is required and local fees may apply for this service.

Services/products providing access to MEDLINE data are also developed and made available by organizations that lease the database from NLM. Access to various MEDLINE services is often available from medical libraries, many public libraries, and commercial sources.

MedlinePlus®, another service offered by the NLM, provides consumer-oriented health information. Health consumers are encouraged to discuss search results with their health care provider.

For further information about MEDLINE send e-mail to or contact NLM toll-free at 1-888-346-3656. For the nearest local medical library in your area contact the NN/LM at 1-800-338-7657.

Related NLM Fact Sheets on the web at are:

See also the MEDLINE®/PubMed® Resources Guide.

Sample Record: PubMed MEDLINE Citation display format

Sample PubMed record in Citation display format

Sample Record: PubMed MEDLINE display format

Sample PubMed record in MEDLINE display format

Last reviewed: 22 April 2008
Last updated: 22 April 2008
First published: 17 November 2004
Metadata| Permanence level: Permanent: Stable Content
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