I found an old post in the Logos 4 forum advising on how it's possible to do a search for an exact word match...
Robert Pavich:
when you want any exact word search just uncheck "match all word forms" under the drop down from the tab.
However, I don't think that works when searching directly within a resource. At present, for example, I have Fr Devin's new book, "Fulfilled in Christ" open. I am searching via Ctrl + F for any mentions of the word "sea", but I keep finding seal and season. Is it possible to restrict the resource search to prevent it searching all word forms within the resource?? I tried searching "sea" and =sea, but to no avail...