The Web of Science provides multidisciplinary literature coverage – including cited references – in the sciences, social sciences, arts, and humanities. Search backward and forward in time with cited reference searching, analyze results, search over 100 years of back files, and link to the full text. Data from 9,300 journals Provides access to Science Citation Index Expanded, Social Sciences Citation Index, and the Arts & Humanities Citation Index

This is the leading abstracting and indexing reference publication for life sciences information. Produced by Biological Abstracts, Inc. (BIOSIS), Biological Abstracts provides references with abstracts derived from thousands of life sciences research journals published worldwide.

PubMed, a service of the National Library of Medicine, provides access to over 16 million MEDLINE citations back to the 1950's and additional life science journals. PubMed includes links to many sites providing full text articles and other related resources. Produced by the National Library of Medicine, MEDLINE is a comprehensive international database of medicine. Covers the fields of medicine, nursing, dentistry, veterinary medicine, the health care system, and the preclinical sciences.

Provides the most accurate and comprehensive chemical and related scientific information. It contains more than 22,000,000 records. One can access information such as: references from journals and patents, substance data, chemical reactions, and more. They have recently included cited references that link to older abstract.