Perhaps you should try some spelling variations:
hanh trang » thanh trung, canh tranh, hanh trinh
nhung cong » dung cong, thong cong, hang cong
hoc hieu » hoc thieu, hoc hien, doc hieu
hieu cac » hieu luc, hieu va, hieu van
trang va » tran van, hang va
cong san » cong tac
phan cau » phan cac, phan tu, phan lap
phan dau » phan tu
hang dau » hang va, hang tai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu cac - hanh trang va nhung cong san ((phan cau) or (((phan dau) OR (hang dau))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu cac - hanh trang va nhung cong san ((phan cau) OR (((phan dau) OR (hang dau)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu cac - hanh trang va nhung cong san ((phan cau) or (((phan dau) OR (hang dau))))".
• Adding a wildcard symbol may retrieve word variants: hoc hieu cac - hanh trang va nhung cong san ((phan cau) or (((phan dau) OR (hang dau))))*.