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