I think the PCAT exam is run on a software which most likely also records what you are doing. I guess you could risk it and try pressing the ctrl+f command and see if it works. I would assume the software will make that command not applicable but if it doesn't, they could also say you were going against the rules of this exam and trash your score.
A calculator and periodic table is provided on the exam. I think they appear as buttons you can press to open them up.
If you attempt to do the search command and your score isn't trashed, let everyone here know. It does make a significant difference on the CR section.