Access is not a database. But it does ship with a default database engine, Jet/ACE. I would assume that's what you mean, but you should be more clear what you mean when you ask a question like this.
Jet/ACE does not have any full-text search capabilities.
The best way to do full-text search of Jet/ACE data files is through whatever full-text search capabilities you have for files on your computer. This is not going to be fast, nor is it going to be usable via SQL.
You don't say what context this is, but I have in general never seen a need for full-text search except on websites (where it's something of an expected capability). If you're using Jet/ACE as the datastore for an HTTP application, then you've chosen the wrong data store. While Jet/ACE can work fine for low-volume read-only websites, that's not an advisable usage (because of limitations in the Jet/ACE database engine).
If you need full-text searching then you need a different database engine.