Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh han
tinh dung » trinh dung, tin dung, tinh quang
hieu suat » hieu luat, hieu qua
tien soat » trien hoat, thien hoat, kiem soat
van hieu » cao hieu
doan van » doan va, hoang van, tran van
van tien » toan tien, van tuan
luan » 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: (( tinh dung luan van hieu suat ) OR ( ((trinh quan) OR (trinh luat)) doan van tien soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung luan van hieu suat ) or ( ((trinh quan) OR (trinh luat)) doan van tien soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung luan van hieu suat ) or ( ((trinh quan) OR (trinh luat)) doan van tien soat ))*.