PubMed Central is a free digital full-text archive of life sciences and medical sciences journal literature, developed and managed by the National Center for Biotechnology Information (NCBI) at the (US) National Library of Medicine (NLM).
A list of the journals included in PubMed Central is available at the PMC Journal List. New journals are continually being added to the database.
The currency and age of material in PubMed Central varies by journal. Many journals make their content available in PMC as soon as it is published. Others may delay release of content in PMC for anywhere from a few months to a few years after publication, but most provide free access to full text within a year of publication.
NLM is digitising the earlier print issues of many of the PubMed Central journals in order to provide online access to the complete run of issues of these journals. PubMed Central has material dating back to mid- to late-1800s or early 1900s for some journals.