Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
tinh thong » tinh thuong, trinh thong, tinh khong
tinh dung » trinh dung, tin dung, tinh quang
quang van » quang ban, quan van, quang uan
hieu suat » hieu luat
kiem soat » kiem toan
quan ke » quan he, quan ve, quan kien
ke kiem » de kiem, ve kiem, mem kiem

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