Perhaps you should try some spelling variations:
hieu manh » chieu xanh, hieu nganh, dieu hanh
tranh xay » trinh xay, manh xay, nganh xay
trong xay » thong xay, trong cac, trong ca
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
phan cau » phan cac, phan tu, phan lap
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 manh - canh ((tranh xay) or (trong xay)) dung cong dan ((phan cau) or (phan dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu manh - canh ((tranh xay) OR (trong xay)) dung cong dan ((phan cau) OR (phan dau)).
• Adding a wildcard symbol may retrieve word variants: doc hieu manh - canh ((tranh xay) or (trong xay)) dung cong dan ((phan cau) or (phan dau))*.