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
cau treo » cau theo, cau tren, cau triet
lang xa » lang ha, dang xay, lang van
hieu va » hieu qua
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
day dan » day danh, dao dan, cay dan
dan vai » dan va, dan tai, dan vat
cuu tre » cua tre, cau tren

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