66. A system comprising: one or more computers; and a computer-readable medium coupled to the one or more computers having instructions stored thereon which, when executed by the one or more computers, cause the one or more computers to perform operations comprising: receiving a search query; generating first search results that identify resources that a search engine has identified as being responsive to the search query; identifying one or more search modes based on the search query, the resources, or both the search query and the resources; providing a first user interface that presents for display at least a portion of the first search results and a respective search mode selector for each of one or more of the identified one or more search modes; receiving user input selecting a first search mode by selecting one of the search mode selectors, wherein: the first search mode is associated with a first collection of records, all records in the first collection have a common attribute structure of data elements, the first search results identify resources that the search engine has identified from a corpus of resources as being responsive to the search query, and all records in the corpus do not have the common attribute structure of data elements; generating second search results that satisfy the search query and that refer to mode-specific records from the first collection of records that are associated with the first search mode, each of the one or more search modes being associated with a particular collection of records from among multiple collections of records; formatting a plurality of the second search results using a mode-specific presentation template that is associated with the first search mode to generate formatted search results; and providing a second user interface that presents for display the formatted search results.
73. The system of claim 66 , wherein: the second user interface further presents a user interface element that allows users to sort the second search results according to values of an attribute that is specific to the first search mode; and the operations further comprise: receiving an indication of a user selection of the user interface element, reordering in the second user interface the second search results in a sorted order according to values of the attribute to generate a revised second user interface, wherein before the user selection the second search results were not presented in the sorted order, and providing the revised second user interface for display.