19. The computer program product of claim 17 , wherein determining, using a document-to-query-to-document model, that the first resource is relevant to a first suggested query different from the initial search query comprises: obtaining a first plurality of previously submitted search queries, each of the first plurality of previously submitted search queries being associated with the first resource identified by the first search result; and selecting a first query from the first plurality of previously submitted search queries as the first suggested query, the first query having at least one term that does not occur in the initial search query.
17. A computer program product, encoded on one or more non-transitory computer storage media, comprising instructions that when executed by one or more computers cause the one or more computers to perform operations comprising: receiving an initial search query; obtaining a plurality of search results responsive to the initial search query, the search results including a first search result that identifies a first resource, the search results including a second search result that identifies a second resource different from the first resource; determining, using a document-to-query-to-document model, that the first resource is relevant to a first suggested query different from the initial search query; determining, using the document-to-query-to-document model, that the second resource is relevant to a second suggested query different from the initial search query and different from the first suggested query; generating a presentation of the search results responsive to the initial search query, wherein each search result in the presentation includes a link to a respective resource, wherein the first search result in the presentation includes a link that, upon a selection by a user, can cause the first suggested query to be submitted to a search engine, and wherein the second search result in the presentation includes a link that, upon a selection by a user, can cause the different second suggested query to be submitted to the search engine; and providing the presentation of the search results in response to the initial search query.