Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
xa hanh » xa thanh, xa khanh, va hanh
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
sac ky » cac ky, sai ky
vi cua » vai cua, di cua
su sac » su sach, su cac, su xac
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: su sac ky nang ((5 hoi) OR (o hoi)). hieu van ((cac tuc) OR (cac tac)) xa hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang ((5 hoi) or (o hoi)). hieu van ((cac tuc) OR (cac tac)) xa hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sac ky nang ((5 hoi) or (o hoi)). hieu van ((cac tuc) OR (cac tac)) xa hanh vi cua tre*.