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