Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cao duc » cao suc, giao duc, tao duoc
vai cua » dai cua, hai cua, lai cua
dao duc » giao duc, tao duoc
cua tre » cua te, cuu tre, cua triet
ly nang » ky nang, ly hang, ly vang
y nang » ky nang, v nang, may nang
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: thu sach ((y nang) or (ly nang)) o hoi. hieu van ((cao duc) OR (dao duc)) van thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((y nang) OR (ly nang)) o hoi. hieu van ((cao duc) OR (dao duc)) van thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((y nang) or (ly nang)) o hoi. hieu van ((cao duc) OR (dao duc)) van thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((y nang) or (ly nang)) o hoi. hieu van ((cao duc) OR (dao duc)) van thanh vai cua tre*.