72. The system of claim 70 , wherein determining that the first search query includes a respective text reference to each of one or more attributes associated with the first entity type comprises: determining that at least one term in the first search query appears in an attribute data store.
70. 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; obtaining search results for the first search query from a search engine, each search result identifying a respective resource; for each of a plurality of the obtained search results, determining an initial score for each of a plurality of entities of the first entity type based on occurrences of names of the entity in the resource identified by the search result; generating a final score for each of the plurality of entities based on the initial scores; selecting one or more names of entities of the first entity type to include in a response to the first search query based on the final scores: and generating one or more attribute suggestions to include in the response to the search query, each attribute suggestion identifying a respective additional attribute associated with the first entity type, wherein generating the one or more attribute suggestions comprises: identifying one or more associated attributes for each of the selected entities; and selecting the associated attributes that maximally refine the selected entities as being attribute suggestions.