16. A system, comprising: a data store storing a query log that includes a set of previous search tokens from previous queries that were received during a current search session; and data processing apparatus including one or more processors configured to interact with the data store and to perform actions including: receiving a current search query during a current search session, the current search query comprising one or more current search tokens; comparing the one or more current search tokens to the set of previous search tokens; identifying, as a potentially inaccurate search token, at least one of the one or more current search tokens that is not included in the set of previous search tokens; identifying a possible replacement token for the potentially inaccurate search token; wherein the possible replacement token is a token with which the potentially inaccurate search token was previously replaced with at least a minimum specified rate; identifying related tokens from a query log based upon previous search queries associated with the current search session; determining whether the possible replacement token for the potentially inaccurate search token is included in the group of related tokens; and in response to determining that the possible replacement token is among the group of related tokens, generating a modified search query that includes the possible replacement token.
16. A system, comprising: a data store storing a query log that includes a set of previous search tokens from previous queries that were received during a current search session; and data processing apparatus including one or more processors configured to interact with the data store and to perform actions including: receiving a current search query during a current search session, the current search query comprising one or more current search tokens; comparing the one or more current search tokens to the set of previous search tokens; identifying, as a potentially inaccurate search token, at least one of the one or more current search tokens that is not included in the set of previous search tokens; identifying a possible replacement token for the potentially inaccurate search token; wherein the possible replacement token is a token with which the potentially inaccurate search token was previously replaced with at least a minimum specified rate; identifying related tokens from a query log based upon previous search queries associated with the current search session; determining whether the possible replacement token for the potentially inaccurate search token is included in the group of related tokens; and in response to determining that the possible replacement token is among the group of related tokens, generating a modified search query that includes the possible replacement token. 20. The system of claim 16 , wherein the one or more processors are further configured to generate a modified search query by performing actions including replacing the potentially inaccurate search token with the possible replacement token in response to determining that the possible replacement token is included in the related tokens.