Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu hien » bieu hien, dieu hien, chieu chien
sach ky » sach y, sach ty, sach kem
cac ban » cac dan, cac van, can ban
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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 ky) OR (sac ky)) nang x hoi. ((thieu nien) or (hieu hien)) cac ban va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang x hoi. ((thieu nien) OR (hieu hien)) cac ban va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) nang x hoi. ((thieu nien) or (hieu hien)) cac ban va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang x hoi. ((thieu nien) or (hieu hien)) cac ban va hanh vi cua tre*.