Perhaps you should try some spelling variations:
doanh doanh » toan doanh, doanh hoan, doanh thanh
doanh giao » danh gia, anh giao, toan giao
hieu lang » chieu sang, hieu quang, nhieu tang
giao tang » gia tang, giao thong, giao thanh
hoc hieu » hoc thieu, hoc hien, doc hieu
cong dan » cong san, cong tan, cong dong
than man » than ma, thanh san, tran manh

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - doanh doanh giao tang ((cong dan) OR (huong dan)) than man~.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - doanh doanh giao tang ((cong dan) or (huong dan)) than man*.