Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
chieu xanh » chieu sach, chieu sang, chieu tinh
hieu xanh » hieu manh, hieu nganh, dieu hanh
trinh qua » trinh quan, trinh cua, trinh quang
dung cong » dung trong
qua dung » quang dung, su dung, qua song
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) OR (chieu xanh)) - canh trinh qua dung cong dan ((khan cap) or (phan dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu xanh) OR (chieu xanh)) - canh trinh qua dung cong dan ((khan cap) OR (phan dau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu xanh) OR (chieu xanh)) - canh trinh qua dung cong dan ((khan cap) or (phan dau))".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) OR (chieu xanh)) - canh trinh qua dung cong dan ((khan cap) or (phan dau))*.