Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
chat xuc » chat huu, cam xuc, chao xu
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang cao hoi. ((hieu van) or (hieu va)) chat xuc ((va hanh) or (ban hanh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. ((hieu van) OR (hieu va)) chat xuc ((va hanh) OR (ban hanh)) dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. ((hieu van) or (hieu va)) chat xuc ((va hanh) or (ban hanh)) dai cua tre*.