ISI maintained citation databases covering thousands of
academic journals, including a continuation of its longtime print-based indexing service the
Science Citation Index (SCI), as well as the
Social Sciences Citation Index (SSCI) and the
Arts and Humanities Citation Index (AHCI). All of these were available via ISI's
Web of Knowledge database service. This database allows a researcher to identify which articles have been cited most frequently, and who has cited them. The database provides some measure of the academic impact of the papers indexed in it, and may increase their impact by making them more visible and providing them with a quality label. Some anecdotal evidence suggests that appearing in this database can double the number of citations received by a given paper. The company's main product was
Current Contents, which gathers the tables of contents for recent academic journals. ISI published
Science Watch, a newsletter which every two months identified one paper published in the previous two years as a "fast-breaking paper" in each of 22 broad fields of science, such as
Mathematics (including
Statistics),
Engineering,
Biology,
Chemistry, and
Physics. The designations were based on the number of citations and the largest increase from one bimonthly update to the next. Articles about the papers often included comments by the authors. The ISI also published a list of "ISI
Highly Cited Researchers", one of the factors included in the
Academic Ranking of World Universities published by
Shanghai Jiao Tong University. This continues under Clarivate. ==History==