Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
cua tre » cua te, cuu tre, cua triet
cao duc » dao duc, cao suc, giao duc
nang xa » nang x, lang xa, mang xa
tai cua » thai cua, tai cuc, tri cua
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
cam duc » cam xuc, pham duc, nam duoc
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san ky ((nang xa) or (nang ma)) hoi. hieu ve ((cam duc) or (cao duc)) van hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky ((nang xa) OR (nang ma)) hoi. hieu ve ((cam duc) OR (cao duc)) van hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu san ky ((nang xa) or (nang ma)) hoi. hieu ve ((cam duc) or (cao duc)) van hanh tai cua tre*.