Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su sach » vu sach
vai cua » dai cua, hai cua, lai cua
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
hang ca » hang va, nang cao, hang tai
ty hang » ly hang, ty xang, thi hang
so sach » so sanh, bo sach, co sach
ca hoi » cau hoi, cua hoi, xa hoi
va cam » va cham, va cac, va cao
vi cua » di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ty hang ca hoi. hieu va cam duc ban thanh ((vi cua) OR (vai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ty hang ca hoi. hieu va cam duc ban thanh ((vi cua) OR (vai cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ty hang ca hoi. hieu va cam duc ban thanh ((vi cua) OR (vai cua)) te".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ty hang ca hoi. hieu va cam duc ban thanh ((vi cua) OR (vai cua)) te*.