Perhaps you should try some spelling variations:
dung hai » dung tai, dung ha, dung sai
sach hoi » sach doi, sach moi, cach thoi
vat dung » van dung, va dung, viet dung
hieu van » thien van, lieu va, hieu ve
sach dao » lanh dao
cao duc » dao duc, cao suc, giao duc
hai cua » thai cua, dai cua, hoi cua
duc vat » duc va, duy vat, duc van
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach dao) or (sach hoi)) lang xa hoi. ((hieu van) or (hieu va)) cao duc vat dung hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach dao) OR (sach hoi)) lang xa hoi. ((hieu van) OR (hieu va)) cao duc vat dung hai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach dao) or (sach hoi)) lang xa hoi. ((hieu van) or (hieu va)) cao duc vat dung hai cua tre*.