Wikipedia
Science.gov is a web portal and specialized search engine. Using federated search technology, Science.gov serves as a gateway to United States government scientific and technical information and research. Currently in its fifth generation, Science.gov provides a search of over 38 databases from 14 federal science agencies and 200 million pages of science information with just one query, and is a gateway to 1,900+ scientific websites.
In 2007, a report to Congress noted that in fiscal year 2007 "Science.gov experienced 6.5 million search queries across all its scientific databases and 2.6 million page views of its website." By 2012, the site had reached 34 million page views annually. In April 2007, Library Journal included Science.gov in its list of best references of 2006. Science.gov is also the United States contribution to the international portal WorldWideScience.