Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
cac duc » cac du, cao duc, cac dac
van cac » van hac, van cau, van bac
ly nang » ky nang, ly hang, ly vang
cuu tre » cua tre, cau tren, cau treo
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 sach ((ly nang) or (ty xang)) x hoi. hieu van cac duc va danh vi ((va triet) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ly nang) OR (ty xang)) x hoi. hieu van cac duc va danh vi ((va triet) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach ((ly nang) or (ty xang)) x hoi. hieu van cac duc va danh vi ((va triet) or (cuu tre))*.