"Europe PubMed Central (Europe PMC) offers free access to biomedical literature resources including:

• PubMed abstracts (about 22 million)
  
• Europe PMC full text articles (about 2.2 million, of which over 400,000 are Open Access)
  
• Patent abstracts (over 4 million European, US, and International)
  
• National Health Service (NHS) clinical guidelines
  Agricola records (500,000)
  
• Supplemented with Chinese Biological Abstracts and the Citeseer database.