Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
canh anh » canh tranh, thanh anh, canh tinh
cong dan » cong san, cong tan, huong dan
cong tac » cong ty
toan cau » toan cao, toan ban, toan tap
anh anh » thanh anh, hinh anh, minh anh

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 - ((canh anh) OR (anh anh)) va nhung ((cong dan) or (cong tac)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - ((canh anh) OR (anh anh)) va nhung ((cong dan) OR (cong tac)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - ((canh anh) OR (anh anh)) va nhung ((cong dan) or (cong tac)) toan cau".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - ((canh anh) OR (anh anh)) va nhung ((cong dan) or (cong tac)) toan cau*.