PubMed Central

PubMed Central is a free database of scientific literature in biomedical and life sciences. It is on the Internet. It grew from the online Entrez PubMed biomedical literature search system. PubMed Central was developed by the U.S. National Library of Medicine (NLM) as an online archive of biomedical journal articles. It was started in 2000. As of 2021, it had over 7 million science papers in it.
All the words in the PubMed Central articles can be read freely. Some publishers, though, do not show their articles for some time after they publish them on paper (usually about six months).
History.
PubMed Central was started in 2000. At first, it only had papers from "Proceedings of the National Academy of Sciences" and "Molecular Biology of the Cell". People can add older papers to PubMed Central. The oldest papers in PubMed Central are from the 1700s.
As of September 2004, PubMedCentral, PubMed, and related NLM services had about 1,300 hits every second, and gave 1.3 terabytes of data every day. The Library of Congress and the British Library showed support for the National Library of Medicine (NLM). It has also been popular with journal service providers.
PubMed Central and PubMed.
PubMed Central is different from PubMed. The regular PubMed has papers' titles and abstracts, and PubMed central has the whole paper. Scientists call this "full text."
PMCID.
The PubMed Central Identifier (PMCID) is an ID tag for papers written by scientists and doctors. It is like an ISBN is for books. It shows the reader where to find the paper in the PubMed Central database.