Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nang dai » nang dau, nang tai, lang dai
hanh vai » hanh va, hanh tai, hanh van
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
dai hoi » dai hoc, dai hai, dai moi
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
so sac » so sach, so dac

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sac ky nang dai hoi. ((hieu ve) or (hieu van)) cam xuc va ((hanh vai) OR (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sac ky nang dai hoi. ((hieu ve) OR (hieu van)) cam xuc va ((hanh vai) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sac ky nang dai hoi. ((hieu ve) or (hieu van)) cam xuc va ((hanh vai) OR (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: so sac ky nang dai hoi. ((hieu ve) or (hieu van)) cam xuc va ((hanh vai) OR (hanh vi)) cua tre*.