1. A method, implemented by one or more computing devices, for performing a search, comprising: receiving a query, and associated query information; identifying context information associated with the query, pertaining to a context in which the query has been submitted; transforming the context information into a context concept vector in a semantic space, using a deep learning model; receiving document information associated with a document, and transforming the document information into a document concept vector in the same semantic space, using the deep learning model, or retrieving a previously generated document concept vector; comparing the context concept vector with the document concept vector to produce a relevance measure, indicating a degree of a defined semantic relationship between the context and the document; determining a ranking score for the document based at least on the relevance measure; and providing a search result based on the ranking score.