Perhaps you should try some spelling variations:
trien hoat » tien hoa
tinh quan » tinh quang, trinh quan, tin quan
hieu soat » hieu suat, hieu luat, kiem soat
hieu hoat » hieu hoa, thien hoat, hieu luat
dinh quan » dinh quang, dinh xuan, dinh duan
quan quan » quan quang, qua quan, quang tuan
van trien » van tien, va trien, van tren
quan van » quan va, quan doan, quang ban
luan » lan

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

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