Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
dang hai » dang khai, hang hai, dung hai
ban dang » ban hang, ban dan, van dang
cao duc » dao duc, cao suc, giao duc
hai cua » thai cua, dai cua, hoi cua
hieu va » lieu va, hieu qua
hieu ve » hieu van
sach ky » sac ky, sach y, sach ty
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
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 ky dang xay hoi. ((hieu ve) OR (hieu va)) ((cao 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 hoi. ((hieu ve) OR (hieu va)) ((cao duc) OR (pham duc)) ban dang hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xay hoi. ((hieu ve) OR (hieu va)) ((cao duc) or (pham duc)) ban dang hai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang xay hoi. ((hieu ve) OR (hieu va)) ((cao duc) or (pham duc)) ban dang hai cua tre*.