Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van
dang hai » dang khai, hang hai, dung hai
ban dang » ban hang, ban dan, van dang
dao duc » giao duc, tao duoc
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van

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 ky ((dang xay) or (van xay)) hoi. hieu ve ((dao duc) or (pham duc)) ban dang hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((dang xay) OR (van xay)) hoi. hieu ve ((dao duc) OR (pham duc)) ban dang hai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((dang xay) or (van xay)) hoi. hieu ve ((dao duc) or (pham duc)) ban dang hai cua tre*.