Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu sang » chieu sang, thieu khang, thieu quang
thien quan » trien quang, lien quan, thien van
trung cua » truong cua, trung tuan, trung cap
dung cong » dung trong
cong vang » cong lang, cong quang, cong ngang
dang bang » dong bang, tang bang, dang quang
dang dang » dang dung, dung dang, dang dan
cua dung » cua dang, cua dong, qua dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sang) or (thien quan)) - thanh trung cua dung cong vang ((dang bang) OR (dang dang))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thien quan)) - thanh trung cua dung cong vang ((dang bang) OR (dang dang)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (thien quan)) - thanh trung cua dung cong vang ((dang bang) OR (dang dang))".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (thien quan)) - thanh trung cua dung cong vang ((dang bang) OR (dang dang))*.