Perhaps you should try some spelling variations:
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
lang ha » long ha
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
duc ban » duc tan, duc van, dua ban
vai cua » hai cua, lai cua, bai 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 sach ky ((nang xa) or (lang ha)) hoi. hieu va pham duc ban hanh ((vai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (lang ha)) hoi. hieu va pham duc ban hanh ((vai cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (lang ha)) hoi. hieu va pham duc ban hanh ((vai cua) or (dai cua)) tre*.