MEDLINE, PubMed, and PMC (PubMed Central): How are they different?
The MEDLINE database is a subset of the PubMed® database. What sets MEDLINE apart from the rest of PubMed is the use of the NLM controlled vocabulary, Medical Subject Headings (MeSH®), to index citations.
PubMed has more than 26 million references including the MEDLINE database plus the following types of citations:
>In-process citations, which provide records for articles before those records are indexed with MeSH or converted to out-of-scope status.
>Citations to articles that are out-of-scope (e.g., covering plate tectonics or astrophysics) from certain MEDLINE journals, primarily general science and general chemistry journals, for which only the life sciences articles are indexed with MeSH.
>"Ahead of Print" citations that precede the article's final publication in a MEDLINE indexed journal.
>Citations that precede the date that a journal was selected for MEDLINE indexing (when supplied electronically by the publisher).
>Pre-1966 citations that have not yet been updated with current MeSH and converted to MEDLINE status.
>Citations to some additional life sciences journals that submit full text to PMC® (PubMed Central®) and receive a qualitative review by NLM.
>Citations to author manuscripts of articles published by NIH-funded researchers.
>Citations for the majority of books available on the NCBI Bookshelf (a citation for the book and in some cases each chapter of the book).