Perhaps you should try some spelling variations:
chieu xanh » chieu sang, chieu tinh, hieu manh
chieu sach » chinh sach, chiet tach, chieu sang
hanh tranh » canh tranh, hanh trinh, hanh trang
trong tap » trong thap, tong tap, trong tan
tranh su » trinh su, trang su, tranh cua
tap toan » tap doan, tap quan, bai 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: theo ((chieu xanh) or (chieu sach)) - hanh tranh su dung trong tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((chieu xanh) OR (chieu sach)) - hanh tranh su dung trong tap toan cau.
• Adding a wildcard symbol may retrieve word variants: theo ((chieu xanh) or (chieu sach)) - hanh tranh su dung trong tap toan cau*.