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