Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
chu bang » thu bang, chuc nang, chu quang
thu hang » thi hang, thuc hanh, thu huong
van hanh » van thanh, ban hanh, van anh
hanh lai » hanh lam, hanh tai, thanh lap
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
lai cua » dai cua, hai cua, lai chau
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: toc sach ((chu bang) or (thu hang)) xa hoi. hieu va cac duc van hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((chu bang) OR (thu hang)) xa hoi. hieu va cac duc van hanh lai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ((chu bang) or (thu hang)) xa hoi. hieu va cac duc van hanh lai cua tre*.