Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cham duc » pham duc, cham soc, pham duy
dang xay » dang van, van xay
va thanh » gia thanh, va tinh, le thanh
so sach » so sanh, bo sach, co sach
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
va cham » va chat, va tham
sach ky » sac ky, sach y, sach ty
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: so sach ky ((dang xay) or (nang x)) hoi. hieu va cham duc ((va thanh) OR (ban thanh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((dang xay) OR (nang x)) hoi. hieu va cham duc ((va thanh) OR (ban thanh)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((dang xay) or (nang x)) hoi. hieu va cham duc ((va thanh) OR (ban thanh)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((dang xay) or (nang x)) hoi. hieu va cham duc ((va thanh) OR (ban thanh)) vai cua tre*.