Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung quan » dung quang, dung luan, luong quan
hieu soat » hieu suat, hieu hoat, hieu luat
tinh dang » binh dang, tinh sang, dinh dang
kiem soat » kiem toan
quan cao » quang cao, quan cau, quan ao
quan van » luan van, quan va, quan doan

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 quan cao hieu soat ) OR ( tinh dang ((quan van) OR (quan luan)) kiem soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung quan cao hieu soat ) or ( tinh dang ((quan van) OR (quan luan)) kiem soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quan cao hieu soat ) or ( tinh dang ((quan van) OR (quan luan)) kiem soat ))*.