PubMed comprises over 30 million citations for biomedical literature from MEDLINE, life science journals, and online books, citations and abstracts dating back to 1966, selectively to 1865, and very selectively to the early 1800's. PubMed is the world's largest database of biomedical and health sciences literature.
PubMedlaunched in 1996, is the interface used to access Medline, PubMed Central, plus additional materials (preprints, pre 1966 citations not yet updated to Medline, NCBI bookshelf, etc.). The earliest literature in PubMed dates back to the early 1800's.
The name PubMed means for Public access to Medline.
MEDLINE is the National Library of Medicine (NLM) journal citation database; previously MEDLARS which launched in 1964.
PubMed Central launched in 2000 as a free archive for full-text biomedical and life sciences journal articles.
MeSH, or Medical Subject Headings, are the National Library of Medicine's controlled vocabulary for indexing articles for MEDLINE/PubMed. Searching by using MeSH provide a consistent way to retrieve information that may use different terminology for the same concepts; locate MeSH using the MeSH database.
NCBI, the National Center for Biotechnology Information, provides a large suite of online resources for biological information and data covering 39 databases that together contain 1.7 billion records, in addition to the NCBI ebook collection, the NCBI bookshelf.
Entrezis NCBI's primary text search and retrieval system that integrates the PubMed database of biomedical literature with 38 other literature and molecular databases.
ClinicalTrials.gov is a database of privately and publicly funded clinical studies conducted around the world hosted by the National Library of Medicine.
LitCovid is is a curated literature hub for tracking up-to-date scientific information about the 2019 novel Coronavirus. It is the most comprehensive resource on the subject, providing a central access to 52899 (and growing) relevant articles in PubMed. The articles are updated daily and are further categorized by different research topics and geographic locations for improved access.