Perhaps you should try some spelling variations:
quang dao » quang cao, quang bao, quang dam
quang dai » quang dam, quang hai, quang ngai
hieu suat » hieu luat, hieu qua
van kien » van tien, van hien, van chien
kien va » khien va, kien van, dien va
tinh » dinh, minh, kinh
luan » quan, lan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh ((quang dao) or (quang dai)) cao hieu suat ) or ( trinh dung luan van kien va ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh ((quang dao) OR (quang dai)) cao hieu suat ) OR ( trinh dung luan van kien va )).
• Adding a wildcard symbol may retrieve word variants: (( tinh ((quang dao) or (quang dai)) cao hieu suat ) or ( trinh dung luan van kien va ))*.