Perhaps you should try some spelling variations:
quang quan » quang tuan, quang uan, quan quan
hieu suat » hieu luat, hieu qua
dinh dung » dinh duong, dinh hung, tinh dung
tuan soat » quan sat, toan hoat, tuan hoan
van tuan » van quan, van ban, anh tuan
quan vi » quan li, quan tri, quan doi
vi hieu » vi dieu, va hieu, vo hieu
tinh » trinh, minh
luan » lan

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

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