Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
xa hanh » xa thanh, xa khanh, va hanh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
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: su sach ky nang ((x hoi) OR (o hoi)). hieu ((van cac) OR (van hac)) tuc xa hanh vi 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) OR (van hac)) tuc xa hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) or (o hoi)). hieu ((van cac) OR (van hac)) tuc xa hanh vi cua tre*.