“(…) provides access to metadata of all items in the PubMed Central (PMC) archive, as well as to the full text of a subset of these items”; full info here.

Suggested entry in ./harvest/oai.ini:

[pubmed]
url = http://www.pubmedcentral.nih.gov/oai/oai.cgi
;set = "pmc-open"
metadataPrefix = oai_dc
idSearch[] = "/^oai:pubmedcentral.nih.gov:/"
idReplace[] = "pubmed-"
idSearch[] = "/\//"
idReplace[] = "-"
injectId = "identifier"
injectDate = "datestamp"

Change “metadataPrefix” entry accordingly to the desired format (mostly because of the level of information provided you might want: oai_dc = basic level, but more easy to parse (XSLT); pmc or pmc_fm = higher level [more metadata], but also more complex to parse).