This post glosses over the fact that F3 is also a standard Windows key command for find. Does that work in Outlook?
As far as I can tell, there is no ctrl+f/F3 style find function in Outlook. You have the search feature, but that behaves differently from ctrl+f.
I've taken to copying email threads and pasting them into Word or Notepad if I need to do a proper find.
^^edit^^
I went out of my way to find out how to do a "find" in Outlook:
ctrl+shift+F for an "advanced" find
F4 for a simple find