Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh cua » doanh cua, manh cua
dang cong » dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
cua dang » cua cong, cua ban
cong dan » cong san, cong tan, huong dan
toan cao » toan ban
toan tap » toan ban

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 tranh cua dang cong dan ((((toan cao) OR (van ban))) OR (toan tap))~.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh tranh cua dang cong dan ((((toan cao) or (van ban))) or (toan tap))*.