Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
hieu ha » hieu hoa, hieu va, hieu ca
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
cua va » cua vat, chua va, cua van
di cua » dai cua, doi cua, de cua
x hoi » o hoi, x ho, 5 hoi

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