Perhaps you should try some spelling variations:
ban thanh » ban hang
thu sach » tu sach, thuat sach, thuoc sach
ban hanh » ban hang
vai cua » dai cua, hai cua, lai cua
van lam » van nam
sach ky » sac ky, sach y, sach ty
van cam » van nam, van cau, van dam
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
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: thu sach ky lang xa hoi. hieu ((van cam) OR (van lam)) duc ((ban thanh) or (ban hanh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky lang xa hoi. hieu ((van cam) OR (van lam)) duc ((ban thanh) OR (ban hanh)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky lang xa hoi. hieu ((van cam) OR (van lam)) duc ((ban thanh) or (ban hanh)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang xa hoi. hieu ((van cam) OR (van lam)) duc ((ban thanh) or (ban hanh)) vai cua tre*.