Perhaps you should try some spelling variations:
tran thanh » ban thanh, van thanh, quan thanh
thanh vai » thanh hai, thanh van, thanh tai
luc tran » buc tranh, luc trong, luc tai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
bao luc » bao thuc
van bao » van ban, van dao
smo hoc » so hoc
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
mo hoc » mon hoc, co hoc
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 ((o hoi) or (((mo hoc) or (smo hoc)))). hieu van bao luc tran thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((o hoi) OR (((mo hoc) OR (smo hoc)))). hieu van bao luc tran thanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((o hoi) or (((mo hoc) or (smo hoc)))). hieu van bao luc tran thanh vai cua tre*.