Perhaps you should try some spelling variations:
cong quang » luong quang, thong quang, duong quang
trinh cong » trinh dung
thien hoat » trien hoat, thien thuat, tien hoa
tinh dung » trinh dung, tin dung, tinh quang
dung quan » dung quang, dung luan, luong quan
hieu soat » hieu suat, hieu hoat, kiem soat
hieu luat » hieu qua
quang van » quang ban, quan van, quang uan
van thien » van tien, van hien, van chien
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: (( tinh dung quan va ((hieu soat) OR (hieu luat)) ) or ( trinh cong quang van thien hoat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quan va ((hieu soat) OR (hieu luat)) ) OR ( trinh cong quang van thien hoat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung quan va ((hieu soat) OR (hieu luat)) ) or ( trinh cong quang van thien hoat ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quan va ((hieu soat) OR (hieu luat)) ) or ( trinh cong quang van thien hoat ))*.