MEDLINE is the largest component of PubMed (http://pubmed.gov), the freely accessible online database of biomedical journal citations and abstracts created by the U.S. National Library of Medicine (NLM). Approximately 5,200 journals published in the United States and more than 80 other countries have been selected and are currently indexed for MEDLINE. A distinctive feature of MEDLINE is that the records are indexed with NLM\'s controlled vocabulary, the Medical Subject Headings (MeSH).In addition to MEDLINE citations, PubMed also contains:
In-process citations which provide a record for an article before it is indexed with MeSH and added to MEDLINE or converted to out-of-scope status.
Citations that precede the date that a journal was selected for MEDLINE indexing (when supplied electronically by the publisher).
Some OLDMEDLINE citations that have not yet been updated with current vocabulary and converted to MEDLINE status.
Citations to articles that are out-of-scope (e.g., cov ...more