Perhaps you should try some spelling variations:
tranh thong » tran thong, tranh trong, trinh thong
tinh dung » trinh dung, tin dung, tinh quang
hieu soat » hieu suat, hieu hoat, hieu so
hieu luat » hieu qua
kiem soat » kiem toan
dung lan » dung luan, dung land, dung lam
lan van » luan van, lang van, tan van
quan ha » quan he
ha kiem » hoa kiem, va kiem, phan kiem

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