Provides an overview of the NIH Public Access Policy and answers the following questions:
PMID = PubMed Identification number
It is a unique number assigned to each article indexed to PubMed. An article receiving a PMID requires no particular effort from the author. A PMID is included in a PubMed Citation below the abstract.
PMCID = PubMed Central Identification number
A PMCID is a PubMed Central Identification Number. PubMed Central is a free full-text archive of the National Institute of Health’s National Library of Medicine. This unique number is assigned to each article submitted to PubMed Central. The PMCID verifies that articles have been submitted to PubMed Central in compliance to the NIH Public Access Policy mandate. Note that not all PubMed citations have a PMCID.