9. 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: receiving a first search query from a user device; receiving first search results for the first search query and a plurality of spelling suggestions for a first misspelled term in the first search query, wherein the first search results are provided by a search engine as a response to the first search query, and wherein a first spelling suggestion of the plurality of spelling suggestions is an aggressive spelling suggestion having an edit distance between the first misspelled term and the first spelling suggestion that is greater than a specified threshold value; generating, for transmission to the user device, a first user interface document that, when rendered, presents a first user interface that displays the plurality of spelling suggestions and the first search results; receiving data identifying a selected spelling suggestion; and generating, for transmission to the user device, a second user interface document that, when rendered, presents a second user interface that displays second search results provided by the search engine for a second search query comprising the selected spelling suggestion in place of the first search results.
11. The system of claim 9 , wherein the specified threshold value is two operations.