The Science Citation Index Expanded provides access to current and retrospective bibliographic information, author abstracts, and cited references found in approximate 5,900 of the world's leading scholarly science and technical journals covering more than 150 disciplines.  The Social Science Citation Index provides access to current and retrospective bibliographic information, author abstracts, and cited references found in over 1,700 of the world's leading scholarly social sciences journals covering more than 50 disciplines. They also cover individually selected, relevant items from approximately 3,300 of the world's leading science and technology journals.