1. A computer-executed method comprising: receiving, from a requesting entity, a search query comprising one or more query words, wherein the one or more query words include a particular keyword; determining whether the particular keyword is a first hint keyword based, at least in part, on detecting, based on a query log, a pattern of usage that identifies the particular keyword as the first hint keyword; wherein the query log comprises a record of a previous search query and an indicator of a particular document in which the requesting entity expressed an interest; and wherein the particular document is from a set of results based on the previous search query; in response to determining that the particular keyword is a first hint keyword, selecting a first set of one or more databases from a plurality of database sets that includes a second set of one or more databases that differs from the first set of one or more databases; searching the first set of one or more databases for at least one query word of the one or more query words; retrieving information regarding a first set of one or more documents resulting from the step of searching the first set of one or more databases; and returning, to the requesting entity, the information regarding the first set of one or more documents.