Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu manh » chieu xanh, hieu nganh, dieu hanh
cua khong » cua phuong, cua thuong, cua cong
hua khong » hoa khong, hoac khong, phuc khong
doc hieu » toc thieu, hoc thieu, hoc hien
phan cau » phan dau, phan cac, phan lap

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 - hanh tranh ((cua khong) or (hua khong)) huong dan ((phan cau) or (phan tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu manh - hanh tranh ((cua khong) OR (hua khong)) huong dan ((phan cau) OR (phan tu)).
• Adding a wildcard symbol may retrieve word variants: doc hieu manh - hanh tranh ((cua khong) or (hua khong)) huong dan ((phan cau) or (phan tu))*.