Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu xanh » chieu xanh, hieu manh, hieu nganh
cua nhung » va nhung
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
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: doc hieu xanh - hanh tranh ((cua cong) or (cua nhung)) cong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh tranh ((cua cong) OR (cua nhung)) cong dan toan cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh tranh ((cua cong) or (cua nhung)) cong dan toan cau*.