Perhaps you should try some spelling variations:
tinh dung » trinh dung, tinh huong, anh dung
hieu soat » hieu suat, hieu hoat, hieu luat
quang tan » quang tuan, quang tran, quang toan
kien soat » kiem soat, bien soan, kien hoa
quan van » luan van, quan va, quan luan
van hieu » cao hieu
van kien » van tien, van hien, van chien
tan van » tran van, tang van, luan van

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) or (tin dung)) quan van hieu soat ) or ( tinh quang tan van kien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((tinh dung) OR (tin dung)) quan van hieu soat ) OR ( tinh quang tan van kien soat )).
• Adding a wildcard symbol may retrieve word variants: (( ((tinh dung) or (tin dung)) quan van hieu soat ) or ( tinh quang tan van kien soat ))*.