Perhaps you should try some spelling variations:
trien hoat » tien hoa
dung quan » dung quang, dung luan, luong quan
van trien » van tien, va trien, van tren
quang ban » quang binh, quang tuan, quang tran
hieu soat » hieu suat, hieu hoat, kiem soat
hieu luat » hieu qua
quan van » luan van, quan va, quan luan
ban van » ban dan, ban va, tan van

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 quan van trien hoat ) OR ( tinh quang ban van ((hieu soat) OR (hieu luat)) ))~.
• Adding a wildcard symbol may retrieve word variants: (( tin dung quan van trien hoat ) or ( tinh quang ban van ((hieu soat) or (hieu luat)) ))*.