Article Sciences
- Scientific article search and order engine, a service provided by Institut de l'Information Scientifique et Technique (INIST) of Centre National de la Recherche Scientifique (CNRS), France.
- http://articlesciences.inist.fr/

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

iSpecies
- A species search engine from Rod Page of Glasgow University. Search on either the common or Latin name of a species. Results are generated by querying other data sources.
- http://darwin.zoology.gla.ac.uk/~rpage/ispecies/

CiteSeer
- 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 P
- http://citeseer.ist.psu.edu/

ISI Highly Cited
- 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/

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

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