Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
hieu soat » hieu suat, hieu hoat, hieu luat
tinh dung » tin dung, tinh quang, tinh huong
van hieu » cao hieu
ban kien » van kien, ban dien, ban tieng
van hien » van tien
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: (( trinh dung luan van hieu soat ) or ( tinh dung quang ((ban kien) or (van hien)) ha ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dung luan van hieu soat ) OR ( tinh dung quang ((ban kien) OR (van hien)) ha )).
• Adding a wildcard symbol may retrieve word variants: (( trinh dung luan van hieu soat ) or ( tinh dung quang ((ban kien) or (van hien)) ha ))*.