Ok, look, you made a noob mistake. If u spend a lot of time for research u should never just leave tabs open and than use it for a next time. Did u heard for option in every browser, called Favorites? Also use it.
CCleaner, what i know from my experience, clean all history on your browser. That also happened with your tabs too. And, as far as i know, u can't get yours tabs back. Sorry! If I am wrog, maybe someone else can correct me and help you more.
P.S. my englisch sucks, sorry for that!