Perhaps you should try some spelling variations:
thien hoat » trien hoat, thien thuat, tien hoa
dung lang » dung dang, dung nang, dung land
hieu suat » hieu luat, hieu qua
tinh quan » tinh quang, trinh quan, tin quan
quan quan » quan quang, qua quan, quan luan
bien soan » bien so
lang van » dang van, tang van, hoang van
van hieu » cao hieu
quan van » luan van, quan va, quan luan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin dung lang van hieu suat ) or ( tinh quan quan van ((bien soan) or (thien hoat)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung lang van hieu suat ) OR ( tinh quan quan van ((bien soan) OR (thien hoat)) )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung lang van hieu suat ) or ( tinh quan quan van ((bien soan) or (thien hoat)) ))*.