Perhaps you should try some spelling variations:
ban hanh » ban hang
cham duc » pham duc, pham duy, phan duc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
sang ma » tang ma, nang ma, sang tao
cua tre » cua te, cuu tre, cua triet
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 ky ((sang ma) or (lang xa)) hoi. hieu ve ((cham duc) OR (cham soc)) ban hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((sang ma) OR (lang xa)) hoi. hieu ve ((cham duc) OR (cham soc)) ban hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((sang ma) or (lang xa)) hoi. hieu ve ((cham duc) OR (cham soc)) ban hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((sang ma) or (lang xa)) hoi. hieu ve ((cham duc) OR (cham soc)) ban hanh vi cua tre*.