Perhaps you should try some spelling variations:
trinh phuong » trinh duong, trinh dung, trinh cong
phuong quang » phung quang, thuong quang, phuong hoang
hieu suat » hieu luat, hieu qua
kiem soat » kiem toan
quang va » quang van, quan va, quang ma
va hieu » van hieu, va dieu, va hien
luan » quan, lan

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

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