Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cuc ban » cua ban, cac ban, cuu ban
xuc ban » duc ban, quoc ban, xuat ban
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang cao
vi cua » vai cua, di cua
ve cac » va cac, vien cac

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