Perhaps you should try some spelling variations:
ban hanh » ban hang
thai cua » than cua, tai cuc, tri cua
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
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 xa) or (nang ma)) hoi. hieu ve pham duc ((van ban) or (ban hanh)) thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu ve pham duc ((van ban) OR (ban hanh)) thai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang ma)) hoi. hieu ve pham duc ((van ban) or (ban hanh)) thai cua tre*.