Perhaps you should try some spelling variations:
thien hoat » trien hoat, thien thuat, tien hoa
van thien » van tien, van hien, van chien
tinh quan » tinh quang, trinh quan, tin quan
quan tran » quang tran, quan tren, xuan tran
hieu suat » hieu luat, hieu qua
van hieu » cao hieu
luan » lan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( trinh dung luan van thien hoat ) or ( tinh quan tran van hieu suat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dung luan van thien hoat ) OR ( tinh quan tran van hieu suat ))*.