  Quantum partial search algorithm is approximate search. It aims to find a
target block (which has the target items). It runs a little faster than full
Grover search. In this paper, we consider quantum partial search algorithm for
multiple target items unevenly distributed in database (target blocks have
different number of target items). The algorithm we describe can locate one of
the target blocks. Efficiency of the algorithm is measured by number of queries
to the oracle. We optimize the algorithm in order to improve efficiency. By
perturbation method, we find that the algorithm runs the fastest when target
items are evenly distributed in database.
