Perhaps you should try some spelling variations:
quang tran » quang tuan, quang trung, quang thanh
tinh huong » dinh huong, anh huong
hieu soat » hieu suat, hieu hoat, hieu luat
tinh dung » trinh dung, tin dung, anh dung
van hieu » cao hieu
van bien » van tien, van hien, vat bien
bien so » bien doi

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 tran van hieu soat ) or ( ((tinh dung) OR (tinh huong)) luan van bien so ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang tran van hieu soat ) OR ( ((tinh dung) OR (tinh huong)) luan van bien so ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh quang tran van hieu soat ) or ( ((tinh dung) OR (tinh huong)) luan van bien so ))*".