Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
tinh khong » tinh khang, tinh huong, benh khong
khong luan » thong luan, khong quan, khung luan
hieu soat » hieu hoat, hieu luat, kiem soat
hieu suat » hieu luat, hieu qua
tien soat » trien hoat, thien hoat, kiem soat
quang vi » quan vi, quang si, quang va
van tien » toan tien, van hieu, van tuan

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