Perhaps you should try some spelling variations:
chien soat » thien hoat
dung thang » hung thang, cung thang, dung thuong
thang van » tang van, thanh van, thong van
hieu soat » hieu suat, hieu hoat, kiem soat
hieu luat » hieu qua
tinh dung » trinh dung, tinh quang, tinh huong
van chien » van hien, van hieu, van tien
luan » quan, lan

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 thang van ((hieu soat) OR (hieu luat)) ) OR ( tinh dung luan van chien soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tin dung thang van ((hieu soat) OR (hieu luat)) ) or ( tinh dung luan van chien soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( tin dung thang van ((hieu soat) OR (hieu luat)) ) or ( tinh dung luan van chien soat ))*.