Standards

Computing, Electrical Engineering, Environmental Practice, Individual Standards, Internet, Organizations, Quality, Standard Document Vendors, Telecommunications, NSSN: A National Resource for Global Standards

Units of Measurement

Online Calculators, Software, All Measures, Anglo-Saxon Weights & Measures, British Weights and Measures Association (BWMA), Conversion Tables, English Weights and Measures, How Many?, IEER Technical Classroom, International System of Units, Metric 4 US, Metric Conversion Tables

Astronomical Constants from NASA

Astronomical/space constants and equations.

Beta-Theta

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

EquationSheet.com

Searchable directory, arranged by field, of equations, constants, symbols and SI units. Also features LaTEX utilities, software links.

GrayLIT Network

Searchable database for reports that are generated by federally funded projects.

Physics and Science Reference by PhysLINK.com

Includes physical constants, online unit conversions, periodic table of elements, exact time, fundamental physical formulae and equations.

RefScout

A weekly, scientific reference mailing service. Screens databases covering life and medical sciences for the key words or the combination of key words specified and will automatically update with any abstract that has come up during the last seven days. Free service.

The Constants and Equations Pages

Expanding reference resource for science, math and astronomy