Perhaps you should try some spelling variations:
quang dung » quang trung, ung dung, cuong dung
tinh dung » tin dung, tinh huong, anh dung
hieu soat » hieu suat, hieu hoat, hieu luat
hien hoat » thien hoat, dien hoat, hieu hoat
van hieu » cao hieu
dung van » duong van, dung va, dang van
van hien » van tien
luan » quan, lan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((tinh dung) OR (trinh dung)) luan van hieu soat ) OR ( tinh quang dung van hien hoat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((tinh dung) OR (trinh dung)) luan van hieu soat ) or ( tinh quang dung van hien hoat ))~".
• Adding a wildcard symbol may retrieve word variants: (( ((tinh dung) OR (trinh dung)) luan van hieu soat ) or ( tinh quang dung van hien hoat ))*.