When searching a document database in response to a search query, a determination is made as to whether a query result corresponding to the search query is stored in a cache. When the query result is stored in the cache, a reuse count for the search query is accessed. When predefined conditions are satisfied, such as the reuse count being larger than a predetermined threshold count, an improved search result is generated in accordance with a first set of predetermined searching criteria, and at least a subset of the improved search result is returned.