Perhaps you should try some spelling variations:
nang mai » nang tai, lang mai, nang cai
vanh dai » van dai, vanh tai, lanh dao
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
qua cao » qua cac, qua ca, qua cai
cao duc » dao duc, cao suc, giao duc
anh dai » anh bai, anh dat, anh tai
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: tu sach ky ((nang mai) or (nang ma)) hoi. hieu qua cao duc va ((anh dai) OR (vanh dai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang mai) OR (nang ma)) hoi. hieu qua cao duc va ((anh dai) OR (vanh dai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang mai) or (nang ma)) hoi. hieu qua cao duc va ((anh dai) OR (vanh dai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang mai) or (nang ma)) hoi. hieu qua cao duc va ((anh dai) OR (vanh dai)) cua tre*.