Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
thien hoat » trien hoat, thien thuat, tien hoa
dung nang » dun nang, dung dang, dung quang
hieu suat » hieu luat, hieu qua
quang van » quang ban, quan van, quang uan
hien soat » kiem soat, bien soan, hien luat
nang van » dang van, tang van, lang van
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 nang van hieu suat ) or ( tinh quang quang van ((hien soat) or (thien hoat)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung nang van hieu suat ) OR ( tinh quang quang van ((hien soat) OR (thien hoat)) )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung nang van hieu suat ) or ( tinh quang quang van ((hien soat) or (thien hoat)) ))*.