Perhaps you should try some spelling variations:
trinh cong » trinh dung
hieu soat » hieu suat, hieu hoat, hieu so
hieu luat » hieu qua
kiem soat » kiem toan
cong san » cong tac
van kiem » va kiem, van kien, van hieu
san van » tan van, tran van, dang van
luan » quan, 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: (( trinh cong san van ((hieu soat) OR (hieu luat)) ) OR ( tin dung luan van kiem soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( trinh cong san van ((hieu soat) or (hieu luat)) ) or ( tin dung luan van kiem soat ))*.