31. A system comprising one or more computers and one or more storage devices storing instructions that when executed by the one or more computers cause the one or more computers to perform operations comprising: determining that a first search query includes a respective text reference to each of one or more predetermined attributes, wherein each attribute is associated with a first entity type; generating a second search query including the first search query and one or more terms that refer to the first entity type; and evaluating search results obtained for the second search query to select one or more names of entities of the first entity type to include in a response to the first search query, wherein each search result identifies a respective search result resource, and wherein evaluating the search results comprises: identifying occurrences of references to entities of the first entity type in the same search result resource as one or more terms from the first search query; and selecting the names of entities based on the identified occurrences.
31. A system comprising one or more computers and one or more storage devices storing instructions that when executed by the one or more computers cause the one or more computers to perform operations comprising: determining that a first search query includes a respective text reference to each of one or more predetermined attributes, wherein each attribute is associated with a first entity type; generating a second search query including the first search query and one or more terms that refer to the first entity type; and evaluating search results obtained for the second search query to select one or more names of entities of the first entity type to include in a response to the first search query, wherein each search result identifies a respective search result resource, and wherein evaluating the search results comprises: identifying occurrences of references to entities of the first entity type in the same search result resource as one or more terms from the first search query; and selecting the names of entities based on the identified occurrences. 34. The system of claim 31 , the operations further comprising: receiving the first search query from a user device; and providing the selected names to the user device for presentation in a user interface, wherein the selected names are presented separately from search results for the first search query.