Perhaps you should try some spelling variations:
chat thuc » thuat thuc, nhan thuc, chat thai
hieu van » hieu va, thien van, lieu va
van chat » cao chat
nang xa » nang x, lang xa, nang ma
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
san ky » sang ky, dan ky, ban ky
va don » va dong, va do, la don

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((san ky) OR (van ky)) nang xa hoi. hieu van chat thuc ((va don) OR (va doc)) vai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((san ky) or (van ky)) nang xa hoi. hieu van chat thuc ((va don) OR (va doc)) vai cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu ((san ky) or (van ky)) nang xa hoi. hieu van chat thuc ((va don) OR (va doc)) vai cua tre*.