Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
sach ky » sac ky, sach y, sach ty
ban dan » ban hang, ban hanh, ban quan
dan dan » dang dan, dao dan, dan dat
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
va cuu » va cau, va chu, va huu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky lang xa hoi. ((hieu va) or (hieu qua)) nam thuc ((dan dan) OR (ban dan)) va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. ((hieu va) OR (hieu qua)) nam thuc ((dan dan) OR (ban dan)) va cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang xa hoi. ((hieu va) or (hieu qua)) nam thuc ((dan dan) OR (ban dan)) va cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. ((hieu va) or (hieu qua)) nam thuc ((dan dan) OR (ban dan)) va cuu tre*.