This paper describes the participation of RePaLi, a team composed with members of IRISA, LIMSI and STL, to the biomedical information retrieval challenge proposed in the framework of CLEF eHealth. For this first participation, our approach relies on a state-of-theart IR system called Indri, based on statistical language modeling, and on semantic resources. The purpose of semantic resources and methods is to manage the term variation such as synonyms, morpho-syntactic variants, abbreviation or

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... sted terms. Different combinations of resources and Indri settings are explored, mostly based on query expansion. For the runs submitted, our system shows up to 67.40 p@10 and up to 67.93 NDCG@10.