Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hanh vai » hanh vi, hanh va, hanh tai
hoc sach » hoc sinh, hoc cac, hoc anh
ban hanh » ban hang
lang van » dang van, tang van, hoang van
vai cua » dai cua, hai cua, lai cua
cac ban » cac dan, cac van, can ban
cam cac » ca cac, nam cac, cam chan
van hoi » van hoa, van hoc, van hoe
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
o lang » hoa lang, hoi lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (((toc sach) OR (hoc sach)))) o lang van hoi. hieu va cam cac ban hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (((toc sach) OR (hoc sach)))) o lang van hoi. hieu va cam cac ban hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (((toc sach) OR (hoc sach)))) o lang van hoi. hieu va cam cac ban hanh vai cua tre*".