Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
xa hanh » xa thanh, xa khanh, da hanh
cac tuc » cac toc, cac tu, cac tac
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
di cua » dai cua, doi cua, de cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 sach ky nang ((x hoi) OR (o hoi)). hieu van cac tuc ((xa hanh) OR (va hanh)) di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((x hoi) or (o hoi)). hieu van cac tuc ((xa hanh) OR (va hanh)) di cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) or (o hoi)). hieu van cac tuc ((xa hanh) OR (va hanh)) di cua tre*.