Perhaps you should try some spelling variations:
chieu tinh » trieu tinh, lieu tinh, chau tinh
chieu sang » chieu sach, chieu xanh, hieu lang
dung cong » dung trong
manh toan » thanh toan, anh tuan, tinh toan
tranh va » tranh van, trang va, trinh va
dan toan » van toan, dan than, xuan toan
va dung » van dung, va duong, vat 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 ((chieu tinh) or (chieu sang)) - canh tranh va dung cong ((dan toan) OR (manh toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu tinh) OR (chieu sang)) - canh tranh va dung cong ((dan toan) OR (manh toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu tinh) or (chieu sang)) - canh tranh va dung cong ((dan toan) OR (manh toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu tinh) or (chieu sang)) - canh tranh va dung cong ((dan toan) OR (manh toan)) cao*.