Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu quang » hieu quang, thien quan, trien quang
trung quang » truong quang, trong quang, trung quan
quang trong » quang truong, quang trung, quan trong
chieu sang » chieu sach, chieu xanh, hieu lang
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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 quang) or (chieu sang)) - thanh trung quang trong cong ((dan toan) OR (van toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu quang) OR (chieu sang)) - thanh trung quang trong cong ((dan toan) OR (van toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu quang) or (chieu sang)) - thanh trung quang trong cong ((dan toan) OR (van toan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu quang) or (chieu sang)) - thanh trung quang trong cong ((dan toan) OR (van toan)) cau*.