Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
vai cua » dai cua, hai cua, lai cua
cao duc » dao duc, cao suc, giao duc
cac duc » cac du, cac dac, cac nuoc
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
sang ma » tang ma, nang ma, sang tao
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky ((sang ma) or (lang xa)) hoi. hieu va ((cac duc) OR (cao duc)) van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((sang ma) OR (lang xa)) hoi. hieu va ((cac duc) OR (cao duc)) van hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((sang ma) or (lang xa)) hoi. hieu va ((cac duc) OR (cao duc)) van hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((sang ma) or (lang xa)) hoi. hieu va ((cac duc) OR (cao duc)) van hanh vai cua tre*.