Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
day thuc » dan thuc, cay thuc, dai thuc
cau treo » cau theo, cau tren, cau triet
lang xa » dang xay, lang van
lang ha » long ha
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, dan vat
vai cau » va cau, van cau, vai cac
va day » va dao, va dau, va dap
va dan » ca dan, va dao, va dau

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 y ((lang xa) or (lang ha)) hoi. hieu va day thuc va dan vai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((lang xa) OR (lang ha)) hoi. hieu va day thuc va dan vai cau treo.
• Adding a wildcard symbol may retrieve word variants: toc sach y ((lang xa) or (lang ha)) hoi. hieu va day thuc va dan vai cau treo*.