Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
van cam » van nam, van lam, van dam
van cau » van dau, van hau, van chat
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
y nang » ky nang, ly nang, v nang
xuc va » duc va, tuc va, luc va
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, x ho, 5 hoi
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 y nang ((x hoi) OR (o hoi)). hieu ((van cam) or (van cau)) xuc va hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (o hoi)). hieu ((van cam) OR (van cau)) xuc va hanh di cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((x hoi) OR (o hoi)). hieu ((van cam) or (van cau)) xuc va hanh di cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) OR (o hoi)). hieu ((van cam) or (van cau)) xuc va hanh di cua vat*.