The ADS (see §3.4.1.) abstract database contained 161,557 abstracts as of October 1993. Five astronomically-related categories of the NASA STI database are used to select relevant abstracts. The data include abstracts from all major journals, many minor journals, NASA reports, and many PhD theses. Users can query by author, object name, keywords, words in the title, and words in the abstract text. Logic within and between these fields can be changed, and the importance of a given word is weighted based on the frequency of that word in the database. The resulting list is ranked by how closely the paper matches the query. From this list, one can obtain all of the information contained in the ADS abstract database (including the bibliographic code, publication date, category, title, authors, author affiliations, keywords, and abstract text). Query feedback capability is provided which uses the results of one query to form another.
Collaboration with SIMBAD (see §3.2.9.) has enabled ADS to provide the capability of searching by object name, and references from SIMBAD are correlated with those in the ADS abstract database. Access to the ADS abstract service is available on the WWW at URL http://adswww.harvard.edu/abstract_service.html.