Perhaps you should try some spelling variations:
tinh luong » tinh huong, dinh luong, minh luong
luong quan » thong quan, duong qua
quang tang » quang thang, quang dang, quang tung
hieu suat » hieu luat, hieu qua
kiem soat » kiem toan
quan van » luan van, quan va, quan luan
van hieu » cao hieu
tang van » dang van, hoang van, trong van
van kiem » va kiem, van kien, van hien

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 van hieu suat ) OR ( tinh quang tang van kiem soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( tinh luong quan van hieu suat ) or ( tinh quang tang van kiem soat ))*.