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

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 do ((cua tre) OR (cuu 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 do ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((nang xa) or (dang xay)) hoi. hieu va cac tac ban thanh do ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang xa) or (dang xay)) hoi. hieu va cac tac ban thanh do ((cua tre) OR (cuu tre))*.