Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
day dao » dan dao, day dan, day danh
cuu tre » cua tre, cau tren, cau treo
hieu va » hieu qua
ky lang » ky dang, ky tang, tay lang
ha hoi » hoa hoi, ha noi, xa hoi
dao va » dao van, tao va, do va
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) OR (ky nang)) ha hoi. ((hieu va) or (lieu va)) nam thuc day dao va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky lang) OR (ky nang)) ha hoi. ((hieu va) OR (lieu va)) nam thuc day dao va cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky lang) OR (ky nang)) ha hoi. ((hieu va) or (lieu va)) nam thuc day dao va cuu tre*".