Perhaps you should try some spelling variations:
chieu xanh » chieu sang, chieu tinh, hieu manh
chieu sach » chinh sach, chiet tach, chieu sang
phuong dan » phuong danh, phuong doan, huong dan
ba trung » tai trung, nam trung, do trung
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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 xanh) OR (chieu sach)) - canh tranh ((cac truong) or (ba trung)) phuong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu xanh) OR (chieu sach)) - canh tranh ((cac truong) OR (ba trung)) phuong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu xanh) OR (chieu sach)) - canh tranh ((cac truong) or (ba trung)) phuong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu xanh) OR (chieu sach)) - canh tranh ((cac truong) or (ba trung)) phuong dan toan cau*.