Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh qua » thanh qua, trinh qua, tranh quang
tranh cua » doanh cua, manh cua
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
khan cap » khan ap, than cap, khoan cam
phan dau » phan tu, hang dau

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 ((tranh qua) or (tranh cua)) dung cong dan ((khan cap) or (phan dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - canh ((tranh qua) OR (tranh cua)) dung cong dan ((khan cap) OR (phan dau)).
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh ((tranh qua) or (tranh cua)) dung cong dan ((khan cap) or (phan dau))*.