Perhaps you should try some spelling variations:
quang tuan » quang thanh, quan luan, quang cua
dung thang » hung thang, cung thang, dung thuong
thang van » tang van, thanh van, thong van
hieu soat » hieu suat, hieu hoat, hieu luat
tuan doan » quan doan, tuan hoan, tan doan
doan dien » toan dien, doan dieu, doan thien
van hieu » cao hieu
dien dan » hien dai, vien dai, gian dan

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 thang van hieu soat ) or ( tinh quang tuan doan dien dan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung thang van hieu soat ) OR ( tinh quang tuan doan dien dan )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung thang van hieu soat ) or ( tinh quang tuan doan dien dan ))*.