EFUNDA: Engineering Reference Resources Major categories are Materials, Processes, Formulas, Design Center, Units & Constants, and Mathematics. There are also a variety of online calculators. Some resources are members-only. Google Patent Search Search and view images of patents issued by the United States Patent and Trademark Office (USPTO), from 1790 - present. For a full search of patent applications and patents use the USPTO database.
MatWeb: Material Property Data This is a searchable collection of data sheets for over 69,000 metals, plastics, ceramics, and composites. Science.gov A gateway to authoritative selected science information
provided by U.S. government agencies, including research and development results.