Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
hieu van » hieu va, thien van, lieu va
vai cua » dai cua, hai cua, lai cua
van lam » van nam
cua tre » cua te, cuu tre, cua triet
xay hoi » xa hoi, tay hoi, cay phoi
xac ky » cac ky, sac ky
xuc va » tuc va, luc va, xac va
bac ky » cac ky, ban ky, sac ky

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su ((xac ky) or (bac ky)) van xay hoi. hieu van lam ((xuc va) OR (duc va)) thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((xac ky) OR (bac ky)) van xay hoi. hieu van lam ((xuc va) OR (duc va)) thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((xac ky) or (bac ky)) van xay hoi. hieu van lam ((xuc va) OR (duc va)) thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((xac ky) or (bac ky)) van xay hoi. hieu van lam ((xuc va) OR (duc va)) thanh vai cua tre*.