Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cac toc » cac toi, cac nuoc, cac thoi
vai cua » dai cua, hai cua, lai cua
va hanh » va thanh, va danh, ban hanh
van cac » van hac, van cau, van bac
nang xa » nang x, lang xa, nang ma
va nang » van nang, da nang, cam nang
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (do sanh)) va nang xa hoi. hieu van cac toc ((va hanh) or (van hanh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (do sanh)) va nang xa hoi. hieu van cac toc ((va hanh) OR (van hanh)) vai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (do sanh)) va nang xa hoi. hieu van cac toc ((va hanh) or (van hanh)) vai cua tre*.