Perhaps you should try some spelling variations:
quang luan » quan luan, quang tuan, quang xuan
dung quan » dung quang, dung luan, luong quan
hieu suat » hieu luat, hieu qua
quang uan » quang tuan, quang ban, quang tran
kien soat » kiem soat, bien soan, kien hoa
quan van » luan van, quan va, quan luan
van hieu » cao hieu
van kien » van tien, van hien, van chien

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

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