Web of Science (access)
WoS is a collection of several databases, among them the Science Citation Index and the Journal Citation Reports. The first product allows you to perform subject, author and title searches, and most importantly it permits to obtain a list of papers citing a specific article, or to navigate to the articles cited by the same article. Besides the retrieval and navigation features, analytical tools allow you to produce statistics and graphs describing the impact of a publication. Finally, the Journal Citation Reports database provides you with the well-known and often-disputed Impact Factor.
1970 to present.
The access is enabled to the whole database.