This research aimed to compare the degree of form and vocabulary match between user's subject queries (user vocabulary) and the List of Persian subject headings (system vocabulary) in two subject areas: 1) Agriculture (applied sciences) 2) library and information science, education, and psychology (humanities). The research population included the students at the two faculties of agriculture and education and psychology. Data were collected through observation and transaction log method. Findings showed that in subject queries carried out by students in the faculty of agriculture, the degree of "full match" was 30.9%, of "partial match" was 19.5%, and of "no match" was 49.6% and in subject queries carried out in the faculty of education and psychology, the degree of "full match" was 37.7%, of "partial match" was 21.1%, and of "no match" was 41.2%. In the two determined faculties, more than 95% of the forms of subject queries accord with those various forms of Persian subject headings more likely used in natural language, including: queries with more than one word simple subject queries and subject queries including several words plus conjunctions and prepositions. There was no significant difference between the search language of the two faculties' students in terms of the degree of match between users' subject queries and Persian subject headings regarding vocabulary and form.