Perhaps you should try some spelling variations:
thien hoat » trien hoat, thien thuat, tien hoa
tinh dung » trinh dung, tin dung, tinh huong
hieu suat » hieu luat, hieu qua
quang uan » quang tuan, quang ban, quang tran
hien soat » kiem soat, bien soan, hien luat
van hieu » cao hieu
uan van » quan van, tan van, san van
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: (( tinh dung luan van hieu suat ) OR ( tinh quang uan van ((hien soat) OR (thien hoat)) ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung luan van hieu suat ) or ( tinh quang uan van ((hien soat) OR (thien hoat)) ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung luan van hieu suat ) or ( tinh quang uan van ((hien soat) OR (thien hoat)) ))*.