Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
quang van » quang ban, quan van, quang uan
hieu suat » hieu luat, hieu qua
tinh nang » trinh nang, tin nang, tich nang
nang quan » ban quan, nang suat
quan minh » quang minh, quan binh, xuan minh
minh hien » minh hieu, minh kieu
hien soat » thien hoat, kiem soat, bien soan
van hieu » cao hieu

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