Perhaps you should try some spelling variations:
sang quang » dang quang, hang quang, tang quang
hieu soat » hieu suat, hieu hoat, hieu luat
tinh sang » tinh quang, tinh trang, trinh san
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: (( tin dung luan van hieu soat ) or ( tinh sang quang van tien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung luan van hieu soat ) OR ( tinh sang quang van tien soat )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung luan van hieu soat ) or ( tinh sang quang van tien soat ))*.