Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung lang » dung dang, dung nang, dung land
hieu suat » hieu luat, hieu qua
quang uan » quang tuan, quang tran, quang chan
quang ban » quang binh, quang tuan, quang tran
kiem soat » kiem toan
lang van » dang van, tang van, hoang van
van hieu » cao hieu
va kiem » van kien

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: (( tinh dung lang van hieu suat ) OR ( tinh ((quang uan) OR (quang ban)) va kiem soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung lang van hieu suat ) or ( tinh ((quang uan) OR (quang ban)) va kiem soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung lang van hieu suat ) or ( tinh ((quang uan) OR (quang ban)) va kiem soat ))*.