Perhaps you should try some spelling variations:
dung quang » dang quang, luong quang, dung luan
quang tuan » quang thanh, quan luan, quang cua
dung quan » dung luan, luong quan, dang quang
hieu suat » hieu luat, hieu qua
kiem soat » kiem toan
van hieu » cao hieu
tuan va » toan va, luan va, quan va
va kiem » van kien

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( trinh ((dung quan) OR (dung quang)) van hieu suat ) or ( tinh quang tuan va kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh ((dung quan) OR (dung quang)) van hieu suat ) OR ( tinh quang tuan va kiem soat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh ((dung quan) OR (dung quang)) van hieu suat ) or ( tinh quang tuan va kiem soat ))".
• Adding a wildcard symbol may retrieve word variants: (( trinh ((dung quan) OR (dung quang)) van hieu suat ) or ( tinh quang tuan va kiem soat ))*.