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
ky lang » ky nang, ky tang, tay lang
hieu ca » hieu cac, hieu cua, hieu va
thuc va » thuc vat, thuc dan, thuc day
dan tai » van tai, dan thi, han tai
cuu tre » cua tre, cau tren
ca nam » cua nam, cai nam, ha nam
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 lang) OR (ky dang)) xa hoi. hieu ca nam thuc va dan tai ((cuu tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky lang) OR (ky dang)) xa hoi. hieu ca nam thuc va dan tai ((cuu tre) OR (cau treo))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky lang) OR (ky dang)) xa hoi. hieu ca nam thuc va dan tai ((cuu tre) or (cau treo))*".