MEDLINE (Medline, Medical Literature Analysis and Retrieval System Online) is a comprehensive literature database of life sciences and biomedical information. It covers the fields of medicine, nursing, dentistry, veterinary medicine, and the health care system. As perhaps a side effect of covering these fields, it also manages to cover nearly all of biology and biochemistry, even covering fields with no direct medical connection, such as molecular evolution. It is compiled by the National Center for Biotechnology Information (NCBI) of the U.S. National Library of Medicine (NLM) and freely available on the Internet through PubMed, searchable with the Entrez engine. Contents 1 The database 2 Impact 3 Medline indexing 4 Usage 5 See also 6 External links The database The database contains over 14 million records from more than 4,800 different publications (mainly medical journals) from the 1950s to today, and new citations are added daily. Newer citations include abstracts of the article in question. It is designed to have global coverage, but most records are from English-language sources or have abstracts in English. MEDLINE uses Medical Subject Headings (MeSH) for information retrieval. Engines designed to search MEDLINE (such as Entrez) generally use a Boolean expression combining 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, 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, to make the search reproducible for other scientists. Additionally, MEDLINE influences researchers in their choice of journals in which to publish. Few researchers today would consider publishing in a journal not indexed by MEDLINE because then other researchers would not find (and cite) their work. Medline indexing Selection of journals for Medline does not have an objective set of criteria. Selection is based on the recommendations of a panel, the Literature Selection Technical Review Committee (LSTRC). The decision whether or not to index a journal is ultimately the responsibility of the Director of the National Library of Medicine. The selection involves considerations of both scientific policy and scientific quality. Publication of objective criteria for inclusion of medical journals is long overdue as perceived subjectivity may lead to Medline being replaced by more modern alternatives, such as Google scholar. However, the LSTRC selection committee are themselves chosen by US government officials. The process is thus open to institutional bias and the selection of journals has been described as a means of censorship in medicine. The Journal of orthomolecular medicine has been repeatedly refused indexing over a period of 35 years leading to claims of bias by Dr Abram Hoffer and Dr Andrew Saul amongst others. Such bias against orthomolecular medicine was a well described feature of the later years of the chemist Linus Pauling who named the discipline. Notably, the Journal of Nutritional and Environmental Medicine which is supported by the British Society for Ecological Medicine has also been refused indexing on both occasions it applied. Usage Although it seems simple, searching Medline effectively is a learned skill. Without some training it is easy to become frustrated by the amount of articles a simple search turns up. Contrarily, it is difficult to be sure that the search is comprehensive, even if it has collected thousands of articles. There are tutorials on using the PubMed interface which explain the ways to get the best out of the site. However, the key skill, framing the correct search string, is not so easily taught. The librarians classify all articles according to subject matter using a standardized vocabulary to describe the subjects - Medical Subject Headings (MeSH). Using the MeSH database to define the subject of interest is one of the most useful ways to improve the quality of a search. Finding one article on the subject and clicking on the "Related Articles" link to get a collection of similarly classified articles is another. See also MedlinePlus health information for patients and health consumers PubChem - an online free chemical service External links JournalReview.org - 'An unbiased forum for review of the medical literature', An On-Line journal club Entrez/PubMed (also available through the shorter link http://pubmed.gov) Cross-database search with Entrez All the databases searcheable with Entrez PubMed Tutorials MeSH database Medline page - Medline Journal Selection Search Term: "Medline" Categories: Bioinformatics | Academic publishing | National Institutes of Health | Search engines | Medical research | Health sciences