Perhaps you should try some spelling variations:
thanh trung » thanh tung
chiet tach » chieu sach
hieu quan » hieu qua, lieu quan, thien quan
trung cua » truong cua, trung tuan, trung cap
cua tong » cua cong, cua dong, cua nong
cong tac » cong ty
toan cau » toan cao, toan ban, toan tap

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chiet tach) OR (hieu quan)) - thanh trung cua tong ((cong san) OR (cong tac)) toan cau~.
• Adding a wildcard symbol may retrieve word variants: ho ((chiet tach) or (hieu quan)) - thanh trung cua tong ((cong san) or (cong tac)) toan cau*.