Retain 4 has a new High Performance Indexer that is more powerful then what was found in eariler versions of Retain but has its own pecularities.
While the documentation discusses the ability to use double quotes (") for doing literal searches it was found in testing that has a significant impact on server performance, that is expected to be resolved in a future release of Retain.
Advanced search allows you to search for terms separately. Use the "word starts with:" for the first term and "word contains:" for the second term to limit the search.
If is part of a larger search this can be put into a group to keep the words together while having other search terms or to be an exclusion of the search terms.