Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
hieu va » lieu va, hieu qua
cac xuc » cam xuc, cac nuoc, chat xuc
xuc van » duc van, luc van, vuc van
cua tre » cua te, cuu tre, cua triet
san ky » sang ky, van ky, ban ky
dan ky » van ky
ma hoi » mai hoi, ma hoa, me hoi

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