Perhaps you should try some spelling variations:
ban thanh » ban hang
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
lai cua » dai cua, hai cua, lai chau
cam duc » cam xuc, cao duc, pham duc
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
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 xa hoi. ((hieu ve) OR (hieu van)) cam duc ((ban thanh) or (ban hanh)) lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam duc ((ban thanh) OR (ban hanh)) lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam duc ((ban thanh) or (ban hanh)) lai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam duc ((ban thanh) or (ban hanh)) lai cua tre*.