An online subscription-based scientific citation indexing service maintained by Thomson Reuters that provides a comprehensive citation search.
An information portal to biological macromolecular structures
A database of chemical and bibliographic information.
A free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).
An annual publication providing information about academic journals in the sciences and social sciences, including impact factors.