Perhaps you should try some spelling variations:
tao hoi » tao khoi, tao boi, thao hoc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
tay hoi » tay ho, tay thai
san ky » sang ky, van ky, dan ky
ve cac » va cac, vien cac
xuc va » tuc va, luc va, xac va
vi cua » vai cua, di cua
tu san » thu san, tu ban, tu can
ky va » ly va, ke va, my va

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