2. The computer-implemented method of claim 1 , wherein obtaining the at least one concept semantically relevant to the first search query comprises: constructing a merged semantic network based on the reference semantic network and the target semantic network; identifying or generating a first concept in the merged semantic network, the first concept representing the user-specified search query; obtaining the at least one concept, including a second concept, semantically relevant to the first concept at least in part by synthesizing the second concept based on the first concept and at least one other concept in the merged semantic network.
2. The computer-implemented method of claim 1 , wherein obtaining the at least one concept semantically relevant to the first search query comprises: constructing a merged semantic network based on the reference semantic network and the target semantic network; identifying or generating a first concept in the merged semantic network, the first concept representing the user-specified search query; obtaining the at least one concept, including a second concept, semantically relevant to the first concept at least in part by synthesizing the second concept based on the first concept and at least one other concept in the merged semantic network. 3. The computer-implemented method of claim 2 , wherein constructing the merged semantic network comprises merging the reference semantic network and the target semantic around a concept the reference semantic network and the target semantic network have in common.