247 Directory

Gives general definitions, background and examples from the science fields of biology, physics, chemistry, math, and history. Includes forum boards.

Expands reference resources for science, maths, and astronomy.

Online resource providing engineering, science, math, physics and chemistry formulae for reference.

Online reference collection used by applied scientists and practicing engineers to quickly locate technical information.

A weekly, scientific reference mailing service.

Descriptions, equations, calculators, conversions and material data for engineering, mathematics, physics and chemistry.