There isn't a place on the "Search" screen, but you just put it in the URL instead.

I'll give you an example, by showing the URL of a profile that I've got open in another browser tab.  The lady's name is Lindsay Love, and her profile is found at: http://www.theeroticreview.com/reviews/show.asp?id=3664 . If you want to see another lady's profile, and you know her profile number, go to the URL box at the top of the screen, change "3664" to whatever the number is that you're looking for, and the profile will appear.