Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thai cua » than cua, tai cuc, tri cua
van hanh » ban hanh, van anh, van ban
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
nang o » nang co, nang ho, nang ro
tu can » tu ban, tu cac, thu canh
tu bac » tu ban, tu cac, tu bat
o lai » o lao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu bac) or (tu can)) ky nang o lai. hieu ve cac dan ((van hanh) or (van thanh)) thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu bac) OR (tu can)) ky nang o lai. hieu ve cac dan ((van hanh) OR (van thanh)) thai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu bac) or (tu can)) ky nang o lai. hieu ve cac dan ((van hanh) or (van thanh)) thai cua tre*.