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
dung cua » dung cho
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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 ((dung cua) or (dung luan)) nhung cong dan than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((dung cua) OR (dung luan)) nhung cong dan than cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((dung cua) or (dung luan)) nhung cong dan than cau*.