Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
van hanh » van thanh, ban hanh, van anh
hanh lai » hanh lam, hanh tai, thanh lap
bang xa » bang va, mang xa, ang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
duc van » duc va, duc tan, duc manh
lai cua » dai cua, hai cua, lai chau
cua tre » cua te, cuu tre, cua triet
va cao » va cac, va co, va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thu ((bang xa) or (lang xa)) hoi. hieu va cao duc van hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu ((bang xa) OR (lang xa)) hoi. hieu va cao duc van hanh lai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach thu ((bang xa) or (lang xa)) hoi. hieu va cao duc van hanh lai cua tre*.