Fragments from the recent Russian meteor are few for now because there have been no long term searches for the fragments and also the fact that despite the explosion, it was a small meteor.
Tunguska was a very large event, many times bigger than the recent Russian meteor. The fact that it flattened such a massive area and nothing has been found from multiples searches and explorations says pretty definitively that it was not meteoric in nature. Even the huge rock that hit the Yucatan millions of years ago left plenty of fragmentary evidence.
Newer research into meteor strikes is calling into question the historical explanation for Tunguska.
The recent Russian event restarted research into the phenomenon.
Airbursts don't leave evidence like earthstrikes do.
I'll see if I can find some of the modern research for you.
/johnny