Perhaps you should try some spelling variations:
doanh doanh » doanh hoan, doanh thanh, dong doanh
hieu manh » chieu xanh, hieu nganh, dieu hanh
luan dang » luan nang, luan danh, luan dong
dang cong » dung cong
hoc hieu » hoc thieu, hoc hien, doc hieu
van toan » van tuan, van tan, van thanh
dan than » dan chan, ban than, van than

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