MEDLINE

Overview
MEDLINE (Medical Literature Analysis and Retrieval System Online) is an international literature database of life sciences and biomedical information. It covers the fields of medicine, nursing, pharmacy, dentistry, veterinary medicine, and health care. MEDLINE covers much of the literature in biology and biochemistry, and fields with no direct medical connection, such as molecular evolution. Listing of an article in MEDLINE does not mean endorsement of that article.

Compiled by the U.S. National Library of Medicine (NLM), MEDLINE is freely available on the Internet and searchable via PubMed and NLM's National Center for Biotechnology Information's Entrez system.

Indexing
MEDLINE uses Medical Subject Headings (MeSH) for information retrieval. Engines designed to search MEDLINE (such as Entrez) generally use a Boolean expressioncombining MeSH terms, words in abstract and title of the article, author names, date of publication, etc. Entrez allows also to find articles similar to a given one based on a mathematical scoring system that takes into account the similarity of word content of the abstracts and titles of two articles.

Impact
MEDLINE functions as an important resource for biomedical researchers and journal clubs from all over the world. Along with the Cochrane Library and a number of other databases, MEDLINE facilitates evidence-based medicine. Most systematic review articles published nowadays build on extensive searches of MEDLINE to identify articles that might be useful in the review. Many articles mention the terms that have been used to search MEDLINE, so that the search is reproducible by other scientists.

Additionally, MEDLINE influences researchers in their choice of journals in which to publish. Few biomedical researchers today would consider publishing in a journal not indexed by MEDLINE, because then other researchers would not find (and cite) their work.

Inclusion of journals
Approximately 5,000 of the world's leading biomedical journals are indexed in MEDLINE. Selection is based on the recommendations of a panel, the Literature Selection Technical Review Committee (LSTRC), based on scientific policy and scientific quality. New journals are not included immediately.

PubMed's Journals Database contains information about each included journal, such as official name abbreviation and URL.

Usage
Searching MEDLINE effectively is a learned skill; untrained users are sometimes frustrated with the large numbers of articles returned by simple searches. Counterintuitively, a search that returns thousands of articles is not guaranteed to be comprehensive.

There are tutorials for instruction on the PubMed interface to MEDLINE. Unlike Google searching of the Web, PubMed searching of MEDLINE requires a little investment of time. Using the MeSH database to define the subject of interest is one of the most useful ways to improve the quality of a search. Using MeSH terms in conjunction with limits (such as publication date or publication type), qualifiers (such as adverse effects or prevention and control), and text-word searching is another. Finding one article on the subject and clicking on the "Related Articles" link to get a collection of similarly classified articles can expand a search that yields few results. In addition to the National Library of Medicine's tutorials, there are several other aids to effective searching, such as pages from a book on MEDLINE usage that can be browsed at Google Book Search.

Online access

 * PubMed
 * GoPubMed - Explore PubMed/MEDLINE with Gene Ontology
 * EBIMed - Explore PubMed/MEDLINE with Gene Ontology and UniProt
 * MeshPubMed - Explore PubMed/MEDLINE with Medical Subject Headings (MeSH)
 * Authoratory - a data-mining interface to PubMed showing author's status, most frequent coauthors, professional interests, affiliated institution, etc.
 * HubMed - An alternative interface to the PubMed medical literature database.
 * eTBLAST - a natural language text similarity engine for MEDLINE and other text databases.
 * BIOWIZARD - a Digg-style site for PubMed/MEDLINE with search functionality through Medical Subject Headings (MeSH)
 * CureHunter - Explore the relationships between diseases, drugs and therapies in PubMed using the MeSH ontology
 * www.medscape.com
 * FABLE - a gene-centric text-mining search engine for MEDLINE
 * Unbound MEDLINE - Clinician-friendly MEDLINE searcing via PDA, wireless devices and the Web
 * PubMed Reader - A free web-based alternative interface for Medline search
 * Twease An open-source biomedical search engine (see source distribution). Twease.org searches MEDLINE. Relevance or chronological searches; highlights text passages that match the query; collects and exports references seamlessly to RefWorks, EndNote, BibTex; searches for articles similar to a group of articles; offers a slider to control query expansion with common synonyms, word variants, mesh terms, etc.; content updated weekly; can be downloaded and setup locally to run thousands of searches against Medline.