Here are some of the key databases for Computer Science. There are many other useful databases, please see the relevant lists under "I'm a Student" or "I'm a Researcher"
ACM Digital Library is a collection of citations and full-text from ACM journals and newsletters and conference proceedings.
The Digital Library is the full-text repository of papers published by the Association for Computing Machinery and by other publishers that have co-publishing or co-marketing agreements with ACM. This includes over 60 years of ACM archives.
Contains one of the most important engineering data sources: Inspec. It includes bibliographic citations and indexed abstracts from publications in the fields of physics, electrical and electronic engineering, communications, computer science, control engineering.
Access to scientific and technical content published by IEEE (Institute of Electrical and Electronics Engineers) and its publishing partners.
Includes transactions, journals, magazines and conference proceedings and all current IEEE Standards. Coverage: 1988 onwards with select content published since 1950.
An abstract and citation database of peer-reviewed literature and quality web sources. Covers more than 15,000 peer-reviewed journals in science, technology, medicine and social sciences.
Current and retrospective multidisciplinary information from thousands of worldwide research journals.
Social Sciences Citation Index (1956 to present), and the Arts & Humanities Citation Index (1975 to present).
Access to several more indexes have been included under the IReL Consortium: for a 3-year period, including:
Conference Proceedings Citation Index; Book Citation Index; Current Chemical Reactions; Index Chemicus. Biosis Citation Index; Current Contents Connect; Data Citation Index; Derwent Innovations Index; Zoological Record. Web of Science also provides cited reference searching.