Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
tinh dung » tin dung, tinh quang, tinh huong
hieu soat » hieu suat, hieu hoat, hieu luat
kiem soat » kiem toan
van hieu » cao hieu
quang va » quang van, quan va, quang ma
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: (( tinh dung (luan OR quan) van hieu soat ) or ( trinh dung quang va kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung (luan OR quan) van hieu soat ) OR ( trinh dung quang va kiem soat ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung (luan OR quan) van hieu soat ) or ( trinh dung quang va kiem soat ))*".