Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
hieu manh » chieu xanh, hieu nganh, dieu hanh
doc hieu » toc thieu, hoc thieu, hoc hien
cua dung » cua dang, cua dong, cua rung
qua dung » quang dung, su dung, qua song
cong dan » cong san, cong tan, huong dan
than cap » khan cap, thanh lap, thanh cac
phan cau » phan dau, phan cac, phan tu

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 manh - canh trinh ((cua dung) OR (qua dung)) cong dan ((than cap) or (phan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu manh - canh trinh ((cua dung) OR (qua dung)) cong dan ((than cap) OR (phan cau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu manh - canh trinh ((cua dung) OR (qua dung)) cong dan ((than cap) or (phan cau))".
• Adding a wildcard symbol may retrieve word variants: doc hieu manh - canh trinh ((cua dung) OR (qua dung)) cong dan ((than cap) or (phan cau))*.