Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
cao duc » dao duc, cao suc, giao duc
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky
ve cao » va cao, ve bao, ve cac
di cua » dai cua, doi cua, de 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 ((sac ky) or (sach ty)) nang ma hoi. hieu ve cao duc ((van hanh) or (ban thanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sach ty)) nang ma hoi. hieu ve cao duc ((van hanh) OR (ban thanh)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sach ty)) nang ma hoi. hieu ve cao duc ((van hanh) or (ban thanh)) di cua tre*.