Perhaps you should try some spelling variations:
tinh luong » tinh huong, dinh luong, minh luong
luong quan » thong quan, duong qua
hieu suat » hieu luat, hieu qua
quang tan » quang tuan, quang tran, quang toan
kien soat » bien soan, kien hoa, dien hoat
kiem soat » kiem toan
quan vo » quan vi, quan va, quan ve
vo hieu » co hieu, va hieu, cao hieu
tan van » tran van, tang van, luan 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: (( tinh luong quan vo hieu suat ) OR ( tinh quang tan van ((kien soat) OR (kiem soat)) ))~.
• Adding a wildcard symbol may retrieve word variants: (( tinh luong quan vo hieu suat ) or ( tinh quang tan van ((kien soat) or (kiem soat)) ))*.