Perhaps you should try some spelling variations:
ban banh » ban hanh, ban anh, ban danh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cac cuc » cac cuoc, cac nuoc, cac cach
cac cua » cach cua, cac qua, ca cua
banh de » hanh de, banh keo, thanh de
de cua » le cua, te cua, dieu cua
cua tu » cua tuc, cua su, cua cu
o hoi » co hoi, o hoc, o hai

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 ((o hoi) or (xa hoi)). hieu va ((cac cuc) OR (cac cua)) ban banh de cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoi) OR (xa hoi)). hieu va ((cac cuc) OR (cac cua)) ban banh de cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((o hoi) or (xa hoi)). hieu va ((cac cuc) OR (cac cua)) ban banh de cua tu".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoi) or (xa hoi)). hieu va ((cac cuc) OR (cac cua)) ban banh de cua tu*.