PubMed is a database run by the United States National Library of Medicine and the National Institute of Health It has more than 24 million citations for biomedical literature from MEDLINE, life science journals, and online books. A PubMed identifier, or a PMID, is a unique number assigned to a PubMed record. It is not the same as a PMCID, which is an identifier given to items published in the free-access PubMed Central.
Note that the assignment of a PMID or PMCID to a publication tells the reader nothing about the type or quality of the content. For more information, see the PubMed homepage: http://www.ncbi.nlm.nih.gov/pubmed.
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