This paper presents the details of participation of DEMIR (Dokuz Eylül University Multimedia Information Retrieval) research team to the Share/CLEF eHealth 2014. This year, we participated to task 3a: monolingual user-centered health information retrieval. In this task, we focused to apply query expansion techniques selectively to some queries to improve the performance of information retrieval. Thus, we first extracted some statistical features from queries such as length of query, sum and intersect of document frequencies of each query term etc. We develop a system to predict if a query is to be expanded or not. Then, we trained our system with previous year's data. Then, we applied a query expansion method only to the queries, which are selected by the system. The results show that the approach we proposed slightly improves our baseline retrieval performance in terms of P@10.