Perhaps you should try some spelling variations:
ban thanh » ban hang
ban hanh » ban hang
su sach » so sach, vu sach
cam dua » ca dua, cay dua, chay dua
san cua » sang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
va cam » va cham, va cac, va cao

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