Perhaps you should try some spelling variations:
thuong quang » truong quang, phuong quang, tuong quang
thong quang » thong quan, thong qua, luong quang
tinh dung » trinh dung, tin dung, tinh quang
hieu soat » hieu suat, hieu hoat, hieu luat
luan bien » luan lien, xuan bien, luong bien
bien soan » bien so
van hieu » cao hieu

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

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