Perhaps you should try some spelling variations:
ban thanh » ban hanh
ban hang » ngan hang
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
ly hang » ly quang
ty hang » ty xang, thi hang, thu hang
ca dua » cay dua, ca cua, ca da
van ca » van cau, van cua, dan ca

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