Perhaps you should try some spelling variations:
te sach » toc sach
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
xay hoi » tay hoi, cay phoi, gay thoi
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua

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

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