Information exploration has become an essential part of exploratory learning that encourages students to acquire new knowledge and solve problems. However, conducting web search is complex and challenging, and learners may fail to acquire valuable information they really need. Recommendation systems have been proposed as a potential means to facilitate learner's web search. Nevertheless, few recommendation systems were developed to help learners obtain more suitable keywords toward a specific field. In this paper, an empirical study was conducted to examine the effectiveness of a proposed recommendation system in facilitating learners to specify keywords more precisely for searching.