Perhaps you should try some spelling variations:
quang tung » quang trung, quang dung, quang hung
dung quan » dung quang, dung luan, luong quan
hieu soat » hieu suat, hieu hoat, hieu luat
hien soat » thien hoat, kiem soat, bien soan
tien hoa » dien hoa, trien hoat, tien va
tung van » trung van, tang van, dung van
van hien » van hieu, van tien
quan va » quan vi, quan ha, luan va

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 quan va ((hieu soat) or (tien hoa)) ) or ( tinh quang tung van hien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung quan va ((hieu soat) OR (tien hoa)) ) OR ( tinh quang tung van hien soat )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung quan va ((hieu soat) or (tien hoa)) ) or ( tinh quang tung van hien soat ))*.