Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
cong cong » cong dong, trong cong, dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
toan cao » toan tap
toan ban » van ban
tinh va » tich va, trinh van, trinh vat
va cong » tai cong, cua cong

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh tinh va cong cong dan ((toan cao) OR (toan ban))~.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh tinh va cong cong dan ((toan cao) or (toan ban))*.