It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Contains reference material covering all major scientific disciplines with articles drawn from McGraw-Hill encyclopedias, dictionaries, and yearbooks, as well as videos, curriculum materials, and links to primary source documents.
An easy-to-use online reference tool for starting research. Gather background information on your topic from hundreds of full-text general and subject-specific reference titles, as well as numerous images, audio files, and video clips.