Perhaps you should try some spelling variations:
tinh huong » dinh huong, anh huong
huong luan » huong lan, cuong luan, huong loan
hieu soat » hieu suat, hieu hoat, hieu luat
quang san » quang ban, quang uan, quang van
dien hoat » dien hoa, dien hat, trien hoat
van hieu » cao hieu
san van » tan van, tran van, dang van
kien ha » kien hoa, kien va, dien hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh huong luan van hieu soat ) or ( tinh quang san van ((dien hoat) or (kien ha)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh huong luan van hieu soat ) OR ( tinh quang san van ((dien hoat) OR (kien ha)) )).
• Adding a wildcard symbol may retrieve word variants: (( tinh huong luan van hieu soat ) or ( tinh quang san van ((dien hoat) or (kien ha)) ))*.