Perhaps you should try some spelling variations:
chieu sang » chieu sach, hieu lang, nhieu tang
chieu xanh » chieu sach, chieu tinh, hieu manh
cua phuong » cuu phuong, cuc phuong, luan phuong
cua khong » hua khong, cua thuong, cua cong
thong bai » thong tai, nhung bai, thong xay
bai toan » bai tap
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sang) or (chieu xanh)) - canh tranh ((cua khong) OR (cua phuong)) thong bai toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sang) OR (chieu xanh)) - canh tranh ((cua khong) OR (cua phuong)) thong bai toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) or (chieu xanh)) - canh tranh ((cua khong) OR (cua phuong)) thong bai toan ban".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (chieu xanh)) - canh tranh ((cua khong) OR (cua phuong)) thong bai toan ban*.