Resource: PubMed Central
PubMed Central (PMC) is the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature.
All the articles in PMC are free (sometimes on a delayed basis). Some journals go beyond free, to Open Access. PMC’s utilities include an OAI service that provides XML of the full-text of some articles, functions for scripting PMC searches and linking to specific PMC articles from your site, and more. Looking for a modern journal article DTD? Take a look at NLM’s Journal Publishing XML DTD and schema. It’s about preservation and access: digitizing the complete run of back issues of many of the journals in PMC.