Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, nghiep nganh
hanh trang » thanh trung, canh tranh, hanh trinh
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, dieu hanh, hien hanh
trang va » tran van, hang va
dan toan » van toan, dan than, manh toan

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 manh) OR (hieu nganh)) - hanh trang va nhung cong ((dan toan) or (anh tuan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (hieu nganh)) - hanh trang va nhung cong ((dan toan) OR (anh tuan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) OR (hieu nganh)) - hanh trang va nhung cong ((dan toan) or (anh tuan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) OR (hieu nganh)) - hanh trang va nhung cong ((dan toan) or (anh tuan)) cau*.