Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
cau treo » cau theo, cau tren, cau triet
dang xay » dang van, van xay
long ha » dong ha, cong ha, dong hoa
lang xa » lang ha, lang van
thuc va » thuc vat, thuc dan, thuc day
va dan » ca dan, va dao, va dau
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 y ((((lang xa) or (dang xay))) or (long ha)) hoi. hieu van nam thuc va dan va cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((((lang xa) OR (dang xay))) OR (long ha)) hoi. hieu van nam thuc va dan va cau treo.
• Adding a wildcard symbol may retrieve word variants: toc sach y ((((lang xa) or (dang xay))) or (long ha)) hoi. hieu van nam thuc va dan va cau treo*.