Where is Subject contains?

In the Refine Search screen for my old rt-3.0.0, one could select
Subject [contains | doesn’t contain | is | isn’t ]. In the new 3.4.1, I
only see Subject [matches | doesn’t match ]. I suspect that this is due
to some new way to include regular expressions in my search. First, is
this correct? Where can I find more information on how to use it if it
is? If that isn’t it, how do I get that functionality back?