Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
tai cuu » tai cuc, tai buu, tai cua
dan tai » van tai, dan thi, han tai
thuc va » thuc vat, thuc day
sach ky » sac ky, sach y, sach ty
hieu va » lieu va
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cuu tre » cua tre, cau tren, cau treo

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