Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
doan hai » doanh tai, hoang hai, doan va
sach ky » sac ky, sach y, sach ty
hai cua » thai cua, dai cua, hoi cua
va doan » va doanh, van doan, va dan
hieu va » lieu va, hieu qua
hieu ve » hieu van
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
cac tu » cac thu, cach tu, tac tu

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 ky lang xa hoi. ((hieu ve) OR (hieu va)) ((cac tu) OR (cac du)) va doan hai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky lang xa hoi. ((hieu ve) OR (hieu va)) ((cac tu) or (cac du)) va doan hai cua tre~".
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang xa hoi. ((hieu ve) OR (hieu va)) ((cac tu) or (cac du)) va doan hai cua tre*.