Perhaps you should try some spelling variations:
quang quan » quang tuan, quang uan, quan quan
tinh dung » tin dung, tinh huong, anh dung
hieu soat » hieu suat, hieu hoat, hieu luat
kien soat » kiem soat, bien soan, kien hoa
quan van » luan van, quan luan, quan doan
van kien » van tien, van hien, van chien
quan va » quan vi, quan ha, luan va
va hieu » van hieu, va dieu, va hien

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