Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
ky dang » ky nang, ky danh
hieu ha » hieu hoa, hieu va, hieu xa
hieu ca » hieu cac, hieu cua, hieu va
ky tang » ky nang, kho tang, ky trong
thuc va » thuc vat, thuc dan, thuc day
dan van » dang van, doan van, dao van
van cau » van dau, van hau, van chat
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 ((ky tang) or (ky dang)) xa hoi. ((hieu ha) or (hieu ca)) nam thuc va dan van cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky tang) OR (ky dang)) xa hoi. ((hieu ha) OR (hieu ca)) nam thuc va dan van cau treo.
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky tang) or (ky dang)) xa hoi. ((hieu ha) or (hieu ca)) nam thuc va dan van cau treo*.