Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh lai » hanh lam, hanh tai, thanh lap
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
lai cua » dai cua, hai cua, lai chau
cua tre » cua te, cuu tre, cua triet
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan 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 nang ((ma hoi) or (xa hoi)). hieu va cac luc van hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky nang ((ma hoi) OR (xa hoi)). hieu va cac luc van hanh lai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu san ky nang ((ma hoi) or (xa hoi)). hieu va cac luc van hanh lai cua tre*.