When throwing, a knife loss energy on the flight, besides, when stabbing the blow goes straight, which is more effective in the case of that kind of weapon. So, no. A throwing knife won't cause the same damage as stabbing.
I've thrown my Bowie Knife about 2 inches into a pine tree. Don't know for certain, cause it was a pain to get it out. I would assume that if a person where in place of that tree, they'd be dead. I haven't stabbed that tree, but I don't imagine I could do much better. Plus that'd hurt if it glanced off. Perhaps a throwing knife isn't quite as powerful as a dagger, but I'd trust that knife to kill just as much thrown as stabbed. I don't know the conversion of pine tree to human flesh, but I think it's safe to say that a pine tree is tougher to get through. I'd be happy to test that out, but I have yet to get any volunteers.