Perhaps you should try some spelling variations:
kiem soat » kiem toan
quang tan » quang tuan, quang tran, quang toan
hieu soat » hieu suat, hieu hoat, hieu luat
dung lan » dung luan, dung land, dung san
dung lam » dung luan, dung tai, dung dat
van hieu » cao hieu
va kiem » van kien
tan van » tran van, tang van, luan van

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin ((dung lan) or (dung lam)) va kiem soat ) or ( tinh quang tan van hieu soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin ((dung lan) OR (dung lam)) va kiem soat ) OR ( tinh quang tan van hieu soat )).
• Adding a wildcard symbol may retrieve word variants: (( tin ((dung lan) or (dung lam)) va kiem soat ) or ( tinh quang tan van hieu soat ))*.