Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cua viet » hoa viet, cua vat, cua dieu
tu sach » thu sach, su sach, te sach
cao duc » dao duc, cao suc, giao duc
ca viet » va viet, co viet, hoa viet
cac duc » cac du, cac dac, cac nuoc
hieu ve » hieu va, hieu van
y nang » ky nang, ly nang, v nang
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 y nang x hoi. hieu ve ((cac duc) OR (cao duc)) van thanh san ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang x hoi. hieu ve ((cac duc) OR (cao duc)) van thanh san ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang x hoi. hieu ve ((cac duc) OR (cao duc)) van thanh san ((cua viet) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang x hoi. hieu ve ((cac duc) OR (cao duc)) van thanh san ((cua viet) or (ca viet))*.