9. A computer system comprising: at least one processor; and memory storing instructions that, when executed by the at least one processor, cause the computer system to perform operations comprising: parse a document from an authoritative source to generate at least one heading-text pair, the text appearing under the heading in the document, assign a topic and a question category to the heading-text pair, store the heading-text pair in a data store keyed by the topic and the question category, determine that a query corresponds to the topic and the question category, generate snippet-based search results by searching an index of documents for documents responsive to the query; and provide the heading-text pair as a natural language search result for the query with the snippet-based search results.
9. A computer system comprising: at least one processor; and memory storing instructions that, when executed by the at least one processor, cause the computer system to perform operations comprising: parse a document from an authoritative source to generate at least one heading-text pair, the text appearing under the heading in the document, assign a topic and a question category to the heading-text pair, store the heading-text pair in a data store keyed by the topic and the question category, determine that a query corresponds to the topic and the question category, generate snippet-based search results by searching an index of documents for documents responsive to the query; and provide the heading-text pair as a natural language search result for the query with the snippet-based search results. 11. The system of claim 9 , wherein the snippet-based results are ranked using a particular ranking algorithm, and wherein the heading-text pairs are ranked using the particular ranking algorithm.