NIST Data Gateway
Provides easy access to scientific and technical data from the US National Institute for Standards and Technology (NIST). These data cover a broad range of substances and properties from many different scientific disciplines.
The Scientific Web
Presents an overview of software programs in biology, chemistry, mathematics, statistics and other scientific disciplines
Bibliographic Databases
Scirus
is a science-specific search engine covering over 105 million science-related pages. It searches both free and journal sources.