Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
trien cua » truyen cua, trien nha, tri cua
tien cua » tiep cua, dien cua, khien cua
so tang » son tang, so trang, do tang
tang ky » dang ky, trong ky, tang khu
qua cac » cua cac
cac tac » cac toc, cac bac, cac dac
tac ban » tai ban, cac ban, tao ban
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

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: so tang ky nang ((x hoi) OR (o hoi)). hieu qua cac tac ban thanh ((tien cua) OR (trien cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so tang ky nang ((x hoi) or (o hoi)). hieu qua cac tac ban thanh ((tien cua) OR (trien cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: so tang ky nang ((x hoi) or (o hoi)). hieu qua cac tac ban thanh ((tien cua) OR (trien cua)) tre*.