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