Scirus is an Internet search engine developed especially to find scientific information.

The site searches more than 55 million science-related pages, including text, PDF and PostScript formatted files. Scirus also claims to search "access controlled sites" and deliver "more peer-reviewed articles than any other search engine." Scirus returns both free and fee-based resources in its results.

Users are given the option of searching for information in any combination of the site's 21 categories ranging from Agricultural, Biological and Life sciences to Sociology (or all of them).

Results are broken down into two easily discernable categories - "Web" and "Membership." While the "Web" resources are available free, the "Membership" results are available for a fee from a variety of partners including BioMedNet/Medline, ChemWeb.com, and ScienceDirect, among others. Charges for these articles vary from site to site.

Scirus, owned by Elsevier Science, is powered by the Norwegian FAST Search and Transfer search engine which also powers the popular AllTheWeb search engine.