The Science Citation Index (SCI) is a citation index originally produced by the Institute for Scientific Information (ISI) and created by Eugene Garfield. It was officially launched in 1964. It is now owned by Thomson Reuters. The larger version (Science Citation Index Expanded) covers more than 6,500 notable and significant journals, across 150 disciplines, from 1900 to the present. These are alternately described as the world's leading journals of science and technology, because of a rigorous selection process.
On July 11, 2016, Thomson Reuters announced that it is selling its science and intellectual property division for $3.55 billion US in cash to a pair of private equity fund managers affiliated with Toronto-based Onex Corp. and Baring Private Equity Asia
The Chemistry Citation Index was first introduced by Eugene Garfield, a chemist by training. His original "search examples were based on [his] experience as a chemist". In 1992 an electronic and print form of the index was derived from a core of 330 chemistry journals, within which all areas were covered. Additional information was provided from articles selected from 4,000 other journals. All chemistry subdisciplines were covered: organic, inorganic, analytical, physical chemistry, polymer, computational, organometallic, materials chemistry, and electrochemistry.