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American Chemical Society, Division of Chemical Information, Education Committee: Computer Searching of Chemical Abstracts: CA File Structure.

CA File Structure

Online files are organized into groups or units of information called indexes. Each index is arranged alphabetically or numerically. Different files contain different indexes which are specifically related to the information contained in the file. Check database guides for listing of specific indexes in each file.

The indexes of a file are organized in a manner similar to drawers in a file cabinet.

The CA file on STN contains these indexes as well as some others.

Chemical Abstracts File Indexes

Basic index includes single words from title and indexing as well as registry numbers.

  • Author Names
    /AU
  • Document Type
    /DT
  • Corporate Source
    /CS
  • Language
    /LA
  • Abstracts
    /AB
  • Publication Year
    /PY

You may specifiy which index to search for the information you are seeking, e.g. pauling/au. If you do not specify an index, the computer assumes you want to search the Basic Index.

The CA Basic Index contains single words from:

NOTE: The Basic Index for CA does not include author names.

Articles, prepositions, and conjunctions are called stop words and are not included in Basic Indexes. In most text files on STN the stopwords are:

  • an
  • for
  • on
  • and
  • from
  • or
  • as
  • in
  • the
  • at
  • not
  • to
  • by
  • of
  • with

Do not use stop words as search terms!