Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
trung dap » trung cap, trung dam, trung lap
trung dai » truong dai, truong dao, trung tam
cong dang » cong dong, cong dung, cong danh
thanh ban » thanh san, thanh van, thanh bac
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu quan - hanh ((trung dap) OR (trung dai)) ung ((cong dang) or (cong dan)) thanh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu quan - hanh ((trung dap) OR (trung dai)) ung ((cong dang) OR (cong dan)) thanh ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu quan - hanh ((trung dap) OR (trung dai)) ung ((cong dang) or (cong dan)) thanh ban".
• Adding a wildcard symbol may retrieve word variants: doc hieu quan - hanh ((trung dap) OR (trung dai)) ung ((cong dang) or (cong dan)) thanh ban*.