Perhaps you should try some spelling variations:
trien hoat » tien hoa
van trien » van tien, va trien, van tren
quang ban » quang binh, quang tuan, quang tran
hieu soat » hieu suat, hieu hoat, hieu luat
van hieu » cao hieu
ban van » ban dan, ban va, tan van
luan » quan, 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: (( tin dung luan van trien hoat ) OR ( tinh quang ban van hieu soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( tin dung luan van trien hoat ) or ( tinh quang ban van hieu soat ))*.