The MEDLINE database, produced by the U.S. National Library of Medicine, is widely recognized as the premier source for citations, indexing, and abstracts of biomedical literature. MEDLINE provides information relevant to the fields of medicine, nursing, and dentistry, and it also covers areas of life sciences, behavioral sciences, chemical sciences, and bioengineering that are related to health and biomedicine. The database contains more than 30 million citations from 5,200 biomedical journals published in the United States and many other countries. It is updated daily with the latest biomedical research. MEDLINE is the electronic counterpart and continuation of the print indexes Index Medicus, Index to Dental Literature, and International Nursing Index.