Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
nam thuc » nam thuoc, am thuc, nam thu
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 nam » van nam, ha nam, va nay
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) or (thuoc sach)) ky ((lang xa) OR (lang ha)) hoi. hieu va nam thuc va dan vai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) ky ((lang xa) OR (lang ha)) hoi. hieu va nam thuc va dan vai cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (thuoc sach)) ky ((lang xa) OR (lang ha)) hoi. hieu va nam thuc va dan vai cau treo".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thuoc sach)) ky ((lang xa) OR (lang ha)) hoi. hieu va nam thuc va dan vai cau treo*.