If the publisher has a WWW site that offers full text of its journals, PubMed provides links to that site. This permits publishers easily to link from references in their published articles directly to entries in PubMed. Finally, PubMed also provides access to the molecular biology databases included in NCBI's Entrez retrieval system. It is expected that access to additional National Library of Medicine databases will be added in the future. The file contains approximately 9 million records dating back to 1966.
Coverage is worldwide, but most records are from English-language sources or have English abstracts.
Publishers may also, at any time, submit corrections and updates of their citations to PubMed. New journals are regularly added. It varies by publisher and journal. Some sites may require that you register, subscribe, or pay a fee in order to view the full text of an article. Contact the journal publishers as noted on their individual Web sites for specific access information.