Back Button Control to Exit Traffic

i wanna to create an script that check where my visits are coming from (referrer) and if they are coming from an search site (google, yahoo) and click on "back button" on browser we do not really back, but we back to the same search site with the same search text but with payed adds. For example : 1. people are seaching for "frases de amor" in google ... then they find my website [login to view URL] and go to there 2. then my site wasn´t what they are looking for, so they click on "back button", but my site return to google serching "frases de amor" but with my adsense code..