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 va » lieu va, hieu qua
hieu ca » hieu cac, hieu cua, hieu xa
ky tang » ky nang, kho tang, ky trong
thuc va » thuc vat, thuc dan, thuc day
dau vai » dau va, dau hai, dau tai
vai cau » va cau, van cau, vai cac
va dau » va dao

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 va) or (hieu ca)) nam thuc va dau vai 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 va) OR (hieu ca)) nam thuc va dau vai cau treo.
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky tang) or (ky dang)) xa hoi. ((hieu va) or (hieu ca)) nam thuc va dau vai cau treo*.