Perhaps you should try some spelling variations:
ban thanh » ban hang
ban hanh » ban hang
su sach » vu sach
so sach » so sanh, bo sach, co sach
ty nang » ky nang, ty xang, ty hang
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
san cua » sang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet

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