CiteSeer Save
Search engine for computer science and related matters. For all results number of citations are given which allows to estimate the importance of a paper in a given context. Most of the papers are cached and available for direct download as postscript or PDF.
http://citeseer.ist.psu.edu/   

ISI Highly Cited Save
A search tool to identify individuals, departments and laboratories that have made fundamental contributions to the advancement of science and technology in recent decades.
http://isihighlycited.com/   

Meta Search Engine for Scientific Literature Save
A multi-search tool that permits queries from scientific journals.
http://www.ojose.com/   

Online Journals Search Engine Save
A multi-search tool that permits queries of a number of scientific journals.
http://ojose.lanners.org/   

SciSeek Save
Science search engine and directory. Also provides forums, tools and related news.
http://www.sciseek.com   

Scirus Save
Search engine that fetches only scientific websites.
http://www.scirus.com/   

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