Perhaps you should try some spelling variations:
cong huong » cong thuong, cong luong, cong hung
hieu manh » chieu xanh, hieu nganh, dieu hanh
doc hieu » toc thieu, hoc thieu, hoc hien
hanh ban » thanh ban, hanh san, hanh han
hang ban » hang luan, hang va, hang tai
phan tap » phan lap, pha tap, phan tu
han tap » han tai, toan tap, nhan tai

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