This historic journal index enables the simultaneous search in millions of citations for articles published in the arts, humanities and social sciences, across more than 300 years. It enables researchers quickly and comprehensively to identify articles relevant to their field of study and reduces what could take years of research to a matter of minutes. Journals indexed span 37 key subject areas and multiple languages.

The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers in astronomy and physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant. The ADS maintains three bibliographic databases containing more than 13 million records covering publications in Astronomy and Astrophysics, Physics, and the arXiv e-prints. Abstracts and full-text of major astronomy and physics publications are indexed and searchable through the new ADS modern search form as well as a classic search form.

SciELO (Scientific Electronic Library Online) is a program of the Sao Paulo Research Foundation for the cooperative publishing of open access journals on the internet. Content includes regional journals from Latin American and the Caribbean as well as titles from Spain, Portugal and South Africa. The index covers approximately 650 titles (over 350 adding content to journals already covered in the Web of Science) and contains several million cited references.