Perhaps you should try some spelling variations:
tinh khung » trinh khung, tinh hung, tinh khang
quang quan » quang tuan, quang uan, quan quan
khung luan » chung luan, dung luan, hang luan
hieu soat » hieu suat, hieu hoat, hieu luat
van hieu » cao hieu
van tien » toan tien, van tuan
quan vi » quan li, quan tri, quan doi
vi hieu » vi dieu, va hieu, vo hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh quang quan vi hieu soat ) or ( tinh khung luan ((van hieu) or (van tien)) soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang quan vi hieu soat ) OR ( tinh khung luan ((van hieu) OR (van tien)) soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh quang quan vi hieu soat ) or ( tinh khung luan ((van hieu) or (van tien)) soat ))*.