Perhaps you should try some spelling variations:
khong xuan » thong xuan, khong quan, khong xuong
tinh khong » tinh khang, tinh huong, benh khong
quan doan » quan hoang, chuan doan, chan doan
hieu suat » hieu luat, hieu qua
bien soan » bien so
van hieu » cao hieu
xuan van » luan van, quan van, xuan can
van bien » van tien, van hien, vat bien
quan va » quan vi, quan ha, luan va

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

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