I have seen a work around on this somewhere. IIRC it involved the use of additional characters that still allowed a return for the root word.
There was a workaround on this board years ago. It stopped working after some kind of software update or server move.
I think short words are completely ignored, T8E's method would produce same results as searching for 'lady' or 'girl'.
Sometimes Google search helps. Search for "tia site:.perb.cc"
However Google won't see the pages that require a PERB login. Most of recent reviews won't be found. You can still search for the Lounge posts, for example.
Advanced search by tags works for short words too, but only if somebody was kind enough to tag that thread that way. Completely manual and requires community effort.