Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
dao duc » giao duc, tao duoc
dao xuc » dao tuc, dao xu, dao xuan
sach da » sach dao, sach dat, sach dau
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
vi cua » vai cua, di cua

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 da ((nang xa) OR (lang xa)) hoi. hieu va ((dao xuc) or (dao duc)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach da ((nang xa) OR (lang xa)) hoi. hieu va ((dao xuc) OR (dao duc)) van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach da ((nang xa) OR (lang xa)) hoi. hieu va ((dao xuc) or (dao duc)) van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach da ((nang xa) OR (lang xa)) hoi. hieu va ((dao xuc) or (dao duc)) van hanh vi cua tre*.