Perhaps you should try some spelling variations:
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, cao hoc, tao hoi
hieu va » lieu va, hieu qua
cam cua » ca cua, nam cua, cau cua
dai cuu » dai huu
co hoi » co hoc, co loi
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: tu sach ky nang ((cao hoi) or (co hoi)). hieu va cam cua ban hanh ((dai cuu) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((cao hoi) OR (co hoi)). hieu va cam cua ban hanh ((dai cuu) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((cao hoi) or (co hoi)). hieu va cam cua ban hanh ((dai cuu) or (dai cua)) tre*.