Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su sach » so sach, vu sach
cam duc » cam xuc, cao duc, pham duc
hoi cua » hoi chuc
hai cua » thai cua, dai cua, lai cua
duc ban » duc tan, duc van, dua ban
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
va cam » va cham, va cac, va cao

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang ma) OR (nang x)) hoi. hieu va cam duc ban thanh ((hai cua) OR (hoi cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang ma) or (nang x)) hoi. hieu va cam duc ban thanh ((hai cua) OR (hoi cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang ma) or (nang x)) hoi. hieu va cam duc ban thanh ((hai cua) OR (hoi cua)) tre*.