In PubMed I sometimes see a link to PMC, PubMed Central, that includes the phrase "author manuscript." Is that article the same as as the version that was published in a journal?
NIH Public Access policy requires "all investigators funded by the NIH submit or have submitted for them to the National Library of Medicine’s PubMed Central an electronic version of their final, peer-reviewed manuscripts upon acceptance for publication, to be made publicly available no later than 12 months after the official date of publication."
The author manuscript version does not look like the pages from the actual journal and usually does not show final page numbers, but it is supposed to be the final version. Many publishers do make the article itself available after publication and those include the journal page numbers. Although freely accessible, articles in PMC are still covered by copyright.
http://www.ncbi.nlm.nih.gov/pubmed/ or www.pubmed.gov
http://www.ncbi.nlm.nih.gov/pmc/ or www.pubmedcentral.gov