The PubMed database now contains >19 million citations dating back to the 1860s from >21 000 life science journals. Over 10.5 million of these citations have abstracts, the earliest from the 1880s, and 10 million of these citations have links to their full-text articles. PubMed is heavily linked to other core Entrez databases, where it provides a crucial bridge between the data of molecular biology and the scientific literature. PubMed records are also linked to one another within Entrez as ‘related articles’ on the basis of computationally detected similarities using indexed Medical Subject Heading (MeSH) (17) terms and the text of titles and abstracts. The default Abstract display format shows the abstract of a paper along with succinct descriptions of the top five related articles and numerous Discovery Components (see above), increasing the potential for the discovery of important relationships.
