Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
tinh dung » tin dung, tinh quang, tinh huong
quang cao » nang cao, quang nam
hieu soat » hieu suat, hieu hoat, hieu luat
kien soat » kiem soat, bien soan, kien hoa
luan va » luan van, luat va
va kien » van kien, va lien, va dien

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 quang cao hieu soat ) or ( trinh dung luan va kien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quang cao hieu soat ) OR ( trinh dung luan va kien soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quang cao hieu soat ) or ( trinh dung luan va kien soat ))*.