Perhaps you should try some spelling variations:
ban hanh » ban hang
cam duc » cam xuc, cao duc, nam duoc
hanh di » hanh vi, hanh de, hang di
hieu ve » hieu va, hieu van
tu sac » tu sach, tu cac, tu san
di cua » dai cua, doi cua, de cua
sac ky » cac ky, sai ky
so hoc » co hoc, mo hoc, so hoa
cua cu » cua chu, cua cau, cua su
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang ((x hoi) or (so hoc)). hieu ve ((cam duc) OR (pham duc)) ban hanh di cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang ((x hoi) OR (so hoc)). hieu ve ((cam duc) OR (pham duc)) ban hanh di cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang ((x hoi) or (so hoc)). hieu ve ((cam duc) OR (pham duc)) ban hanh di cua cu".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((x hoi) or (so hoc)). hieu ve ((cam duc) OR (pham duc)) ban hanh di cua cu*.