Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
hanh tran » hanh trang, thanh tran, hanh tram
van phung » van phong, van hung, van chuong
hoc hieu » hoc thieu, hoc hien, doc hieu
tran van » luan van
cong ban » cong bang, cong san, cong dan
cong tan » cong tac, cong san, cong thanh
than man » thanh san, tran manh, than phan
than ma » than va, khan ma, nhan ma

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu quan - hanh tran van phung ((cong ban) OR (cong tan)) ((than man) or (than ma))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu quan - hanh tran van phung ((cong ban) OR (cong tan)) ((than man) OR (than ma)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu quan - hanh tran van phung ((cong ban) OR (cong tan)) ((than man) or (than ma))".
• Adding a wildcard symbol may retrieve word variants: hoc hieu quan - hanh tran van phung ((cong ban) OR (cong tan)) ((than man) or (than ma))*.