عنوان مقاله [English]
Expansion of search query is aimed at improving the relevant [search] results or acquiring appropriate sources for current or future research. It takes place when users are dissatisfied with their search results or have obtained insufficient results. Vocabulary control tools headed by online thesauri are among the resources used for expanding search query. The present paper attempts to empirically demonstrate the impact of using terms from ERIC Online Thesaurus [ERICOT] in expanding search queries. Comparison of searches conducted by both test and control groups during pre- and post-test demonstrated that using ERICOT played a significant role in improving the search questions and duration. Using broader, narrower and related terms found in the thesaurus altered the precision of retrieval. Using broader and related terms increased the search time.