Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung quan » dung quang, dung luan, luong quan
hieu soat » hieu suat, hieu hoat, hieu luat
tien soan » bien soan, tien hoang, thien toan
quan van » luan van, quan va, quan luan
van hieu » cao hieu
lan toan » van toan, dan toan, manh toan
lap toan » tap toan, lap doanh, phap toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh dung quan van hieu soat ) or ( tinh dung ((lan toan) OR (lap toan)) tien soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quan van hieu soat ) OR ( tinh dung ((lan toan) OR (lap toan)) tien soan )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung quan van hieu soat ) or ( tinh dung ((lan toan) OR (lap toan)) tien soan ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quan van hieu soat ) or ( tinh dung ((lan toan) OR (lap toan)) tien soan ))*.