Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
sach ly » sach y, sach lo, sach ty
hieu va » lieu va, hieu qua
ly vang » ly hang, ly van, ly quang
hieu ve » hieu van
cuu tre » cau tren, cau treo
xuc va » duc va, tuc va, luc va
vang o » lang o, tang o, vung o
o hoi » co hoi, o hoc, o hai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ly vang o hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ly vang o hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi ((cua tre) or (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: thu sach ly vang o hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi ((cua tre) or (cuu tre))*.