The magazine, Bulletin of the Atomic Scientists , began in the 1940's to keep the public informed about nuclear weapons. It remains one of the best sources of information on this topic. Martindale's Calculators On-Line Calculators for just about anything. Major sub-categories are mathematics, science and engineering. NIST Reference on Constants, Units and Uncertainty Search for physical constants by name.
Site provides basic data on each constant.
A Periodic Table of the Elements at Los Alamos National Laboratory Periodic table displayed in standard format. These journals are written for non-biology majors and are easy to understand. 1994 to the present. A bibliographical database that cites articles from more than 240 periodicals. Periodical coverage includes a wide range of scientific journals, from popular to professional, that pertain to biology and agriculture.