Perhaps you should try some spelling variations:
bong quang » hong quang, dong quang, long quang
cong quang » luong quang, thong quang, duong quang
chien soat » thien hoat
hieu soat » hieu suat, hieu hoat, hieu luat
luat luan » luat quan, luat luat, luat quang
van chien » van hien, van tien
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: (( trinh ((bong quang) OR (cong quang)) van hieu soat ) or ( trinh luat luan van chien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh ((bong quang) OR (cong quang)) van hieu soat ) OR ( trinh luat luan van chien soat ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh ((bong quang) OR (cong quang)) van hieu soat ) or ( trinh luat luan van chien soat ))*".