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

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 qluan) OR (dung quan)) van hieu suat ) or ( tinh quang luan van kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh ((dung qluan) OR (dung quan)) van hieu suat ) OR ( tinh quang luan van kiem soat ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh ((dung qluan) OR (dung quan)) van hieu suat ) or ( tinh quang luan van kiem soat ))*".