Aids to Searching 

Subject searching in OPAC creates certain problems for the users. Several OPACs have been developed to ease vocabulary selection and aid in searching. When the user is having trouble in finding the correct controlled vocabulary term to use for searching, a in resulting display of records with the message that the retrieved records have the subject words in their titles and their headings' will be useful in the search. Subject headings on the records help to find controlled vocabulary for the desired topic. Thus, OPACs offer the opportunity in guiding the users from natural language terms in titles to the controlled vocabulary used in subject headings.