Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
tuong quan » truong quan, thong quan, cuong quan
luong quan » thong quan, duong qua
quang ban » quang binh, quang tuan, quang tran
hieu soat » hieu suat, hieu hoat, hieu luat
hien soat » thien hoat, kiem soat, bien soan
ban hieu » van hieu, gian hieu, phan hieu
van hien » van hieu, van tien
tin » tinh

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