Perhaps you should try some spelling variations:
trinh tang » trinh trang, trinh tong, trinh bang
dung quan » dung quang, luong quan, dang quang
hieu soat » hieu suat, hieu hoat, hieu luat
kiem soat » kiem toan
so hieu » co hieu, so dieu, so lieu
luan va » luan van, luat va
va kiem » van kien
tin » tinh

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin ((dung quan) OR (dung luan)) so hieu soat ) OR ( trinh tang luan va kiem soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tin ((dung quan) OR (dung luan)) so hieu soat ) or ( trinh tang luan va kiem soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( tin ((dung quan) OR (dung luan)) so hieu soat ) or ( trinh tang luan va kiem soat ))*.