CAS ONLINE-Chemical substance search system

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  • Hirota Yuji
    Japan Association for International Chemical Information

Bibliographic Information

Other Title
  • CAS ONLINE : CAS化学物質検索システム
  • CAS ONLINE CAS カガク ブッシツ ケンサク システム

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Description

Chemical Abstracts Service entered the field of online service based on chemical structures with its own system called CAS ONLINE. The system has been accessible since Dec. 1980 in Japan. CAS ONLINE made it possible to search a large chemical substance file derived from the CAS Chemical Registry System using the chemical structure which is familier to the chemist as a search term. The search results contains chemical structure diagrams and the CAS Registry Numbers which are in turn used as search terms in the document search. The chemical substance file of CAS ONLINE contains about 2,000,000 compounds which is the largest chemical structure file searchable on-line. When a search is to be performed, the searcher analyzes the query structure to identify distinctive structural features or fragments, locates the corresponding search screens in the screen dictionary, and constructs a search profile containing screen numbers and sets of screen numbers combined with Boolean logic. The large structure file is divided into several segments which are searched in parallel by minicomputers. Each minicomputer holds records for about 750,000 substances and it takes about five minutes to search its full file. CAS ONLINE system features and a search example are described.

Journal

  • Dokumenteshon kenkyu

    Dokumenteshon kenkyu 31 (5), 201-208, 1981

    Information Science and Technology Association, Japan

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