Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh huong
dung lang » dung dang, dung nang, dung land
hieu suat » hieu luat, hieu qua
kiem soat » kiem toan
lang van » dang van, tang van, hoang van
van hieu » cao hieu
uan va » luan va, quan va, dan va

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 va) OR (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 va) OR (ban va)) kiem soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung lang van hieu suat ) or ( tinh quang ((uan va) OR (ban va)) kiem soat ))*.