Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh huong
hieu hoat » hieu hoa, thien hoat, hieu suat
hieu luat » hieu qua
quang uan » quang tuan, quang ban, quang tran
kiem soat » kiem toan
dung lan » dung luan, dung land, dung lam
lan van » luan van, lang van, tan van
va kiem » van kien
uan va » luan va, quan va, ban va

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

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