Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hoi cua » hoi chuc
cac do » cac don, cac doi, cac du
x hoi » xa hoi, o hoi, x ho
do va » do van, so va

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