Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
tai cuu » tai cuc, tai buu, tai cua
dan tai » van tai, dan thi, han tai
thuc va » thuc dan, thuc day
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
va nam » van nam, ha nam
va nay » va ngay, va cay

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: doc sach ky tang xa hoi. hieu ((va nam) OR (va nay)) ((thuc va) OR (thuc vat)) dan tai cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky tang xa hoi. hieu ((va nam) OR (va nay)) ((thuc va) or (thuc vat)) dan tai cuu tre~".
• Adding a wildcard symbol may retrieve word variants: doc sach ky tang xa hoi. hieu ((va nam) OR (va nay)) ((thuc va) or (thuc vat)) dan tai cuu tre*.