Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
kiem soat » kiem toan
luan nang » van nang, luan san
hieu soat » hieu suat, hieu hoat, hieu luat
van kiem » va kiem, van kien, van hien
quan san » luan san, quan sat, quan van
van hieu » cao hieu

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 kiem soat ) OR ( tinh ((quan san) OR (luan nang)) van hieu soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( tinh dung luan van kiem soat ) or ( tinh ((quan san) or (luan nang)) van hieu soat ))*.