Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
chieu xanh » chieu sang, chieu tinh, hieu manh
tang nguoi » thang nguoi, nang nguoi, thanh nguoi
tang nguon » tang nguyen, dung nguon, bang ngon
tranh ca » tranh cua, tranh cac, tranh cai
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: doi ((chieu sach) or (chieu xanh)) - canh tranh ca ((tang nguoi) OR (tang nguon)) dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chieu sach) OR (chieu xanh)) - canh tranh ca ((tang nguoi) OR (tang nguon)) dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((chieu sach) or (chieu xanh)) - canh tranh ca ((tang nguoi) OR (tang nguon)) dan toan cau".
• Adding a wildcard symbol may retrieve word variants: doi ((chieu sach) or (chieu xanh)) - canh tranh ca ((tang nguoi) OR (tang nguon)) dan toan cau*.