Perhaps you should try some spelling variations:
trinh phuong » trinh duong, trinh dung, trinh cong
quang quang » quan quang, dang quang, dung quang
phuong luan » phuong lan, phong luan, phuong loan
hieu hoat » hieu hoa, thien hoat, hieu suat
hieu luat » hieu qua
kien soat » kiem soat, bien soan, kien hoa
quang vi » quan vi, quang si, quang va
van kien » van tien, van hien, van chien
tinh » dinh, minh, kinh

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 vi ((hieu hoat) OR (hieu luat)) ) or ( trinh phuong luan van kien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang quang vi ((hieu hoat) OR (hieu luat)) ) OR ( trinh phuong luan van kien soat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh quang quang vi ((hieu hoat) OR (hieu luat)) ) or ( trinh phuong luan van kien soat ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh quang quang vi ((hieu hoat) OR (hieu luat)) ) or ( trinh phuong luan van kien soat ))*.