Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
tinh luong » tinh huong, minh luong, tinh cuong
dinh luong » dinh duong, dinh huong, dinh cuong
quang van » quang ban, quang uan, quang va
hieu soat » hieu suat, hieu hoat, hieu luat
kiem soat » kiem toan
van hieu » cao hieu
quan van » luan van, quan va, quan luan
van kiem » va kiem, van kien, van hien

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh quang quang van hieu soat ) or ( ((tinh luong) OR (dinh luong)) quan van kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang quang van hieu soat ) OR ( ((tinh luong) OR (dinh luong)) quan van kiem soat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh quang quang van hieu soat ) or ( ((tinh luong) OR (dinh luong)) quan van kiem soat ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh quang quang van hieu soat ) or ( ((tinh luong) OR (dinh luong)) quan van kiem soat ))*.