Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
kho tang » cao tang
cham duc » pham duc, cham soc, pham duy
cua tre » cua te, cuu tre, cua triet
tai cua » thai cua, tai cuc, tri cua
anh tai » hanh tai, anh thai, vanh tai
hieu va » lieu va
tang xa » trang xa, tang ma, lang xa
va anh » van anh, va danh, va hanh
te sac » te sach, te cac, te san

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sac) or (toc sach)) kho tang xa hoi. ((hieu va) or (hieu qua)) cham duc va anh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sac) OR (toc sach)) kho tang xa hoi. ((hieu va) OR (hieu qua)) cham duc va anh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sac) or (toc sach)) kho tang xa hoi. ((hieu va) or (hieu qua)) cham duc va anh tai cua tre*.