The Exact module provides a finer grained (but more computationally expensive) alternative to the Phrase module.
The Exact module is computationally expensive, especially on large text fields. It is intended for use only on small text fields (such as managed attribute values or small managed attribute values like part IDs). This module should not be used with large or offline documents. Use of this module in these cases will result in very poor performance and/or application failures due to request timeouts. The Phrase module, with and without approximation turned on, does similar but less sophisticated ranking that can be used as a higher performance substitute.