Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
hieu soat » hieu suat, hieu hoat, hieu luat
kien soat » kiem soat, bien soan, kien hoa
van hieu » cao hieu
quan van » quan luan, quan doan, quang ban
quan va » quan vi, quan ha, luan va
luan » lan

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