Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
tinh dung » trinh dung, tin dung, tinh huong
hieu soat » hieu suat, hieu hoat, hieu luat
quang van » quang ban, quan van, quang uan
tien soat » trien hoat, thien hoat, kiem soat
van hieu » cao hieu
van tien » toan tien, van tuan
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 dung luan van hieu soat ) OR ( tinh quang quang van tien soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung luan van hieu soat ) OR ( tinh quang quang van tien soat ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung luan van hieu soat ) OR ( tinh quang quang van tien soat ))*.