1. A topic-based search query system, comprising: a memory that stores computer executable components; and a microprocessor that executes the following computer executable components stored in the memory: an input component that receives a query; a mapping component that maps the query to a set of domain topics, wherein a domain topic from the set of domain topics is mapped to the query based upon a first conditional probability, P(T|Q), of the domain topic given the query; a results component that identifies a set of results for the query, wherein a result from the set of results is identified based upon a second conditional probability, P(R|T), of the result given the domain topic; and an output component that presents the set of results.