Perhaps you should try some spelling variations:
thanh tung » thanh cong
duong cong » luong cong, duong trong, trong cong
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
tung hoc » trung hoc, tuong hoc, dung hoc
than cau » toan cau, phan cau, thanh chau
than cap » khan cap, thanh lap, thanh cac
ho hieu » ho chieu, hoi hieu, nho hieu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - thanh tung hoc ((duong cong) OR (dung cong)) sang ((than cau) OR (than cap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - thanh tung hoc ((duong cong) OR (dung cong)) sang ((than cau) or (than cap))~".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - thanh tung hoc ((duong cong) OR (dung cong)) sang ((than cau) or (than cap))*.