Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
dang xay » dang van, van xay
thanh de » hanh de, thanh ve, thanh do
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac tac » cac toc, cac bac, cac dac
tac ban » tai ban, cac ban, tao ban
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky ((nang xa) or (dang xay)) hoi. hieu va cac tac ban thanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((nang xa) OR (dang xay)) hoi. hieu va cac tac ban thanh de cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang xa) or (dang xay)) hoi. hieu va cac tac ban thanh de cua tre*.