9. The system of claim 7 , 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.
9. The system of claim 7 , 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. 10. The system of claim 9 , the operations further comprising: associating the first resource with the first plurality of previously submitted search queries based on user behavior data when the first resource is identified by search results provided to users as responsive to the first plurality of previously submitted search queries.