Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
hanh tranh » canh tranh, hanh trinh, hanh trang
tranh cua » doanh cua, manh cua
cong cong » cong dong, trong cong, dung cong
ho chieu » theo chieu, hoc thieu, doi chieu
bai toan » bai tap
van toan » van tuan, van tan, van thanh

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho chieu xanh - hanh tranh cua cong cong ((bai toan) OR (van toan)) cau~.
• Adding a wildcard symbol may retrieve word variants: ho chieu xanh - hanh tranh cua cong cong ((bai toan) or (van toan)) cau*.