You can see it on a chart of interest rates for the past 3 years. During QE1 and QE2, interest rates actually rose (because the QE increased inflation expectations). When both QE's ended, interest rates fell and bond prices rose. Why do so many people seem to think this time is different?
Because QE was just an excused for the bonds. Stocks went lower when it ended, so it was really all about Ben's buddies on wall street that wanted to juice for the equities. QE is good for the stock market.
I might add that bond prices also rose (and yields fell) at the end of 'Operation Twist'. And the current QE3 has resulted in lower bond prices and higher yields. So all of Bernanke's bond-buying has actually accomplished the opposite of his stated intentions. It's counter-productive.