Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
so sach » bo sach, co sach, hoc sach
so sanh » do sanh
nang xa » nang x, lang xa, nang ma
hieu he » hieu ve, hiem he, hieu le
thuc va » thuc vat, thuc dan, thuc day
va lang » va nang, hoa lang
lang di » lang dai, hang di, lang du
cuu tre » cua tre, cau tren, cau treo
he nam » ha nam, nghe nam
di cuu » di cau, di cua, dinh cuu

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 (((so sach) OR (so sanh)))) ky nang xa hoi. hieu he nam thuc va lang di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (((so sach) OR (so sanh)))) ky nang xa hoi. hieu he nam thuc va lang di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (((so sach) OR (so sanh)))) ky nang xa hoi. hieu he nam thuc va lang di cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (((so sach) OR (so sanh)))) ky nang xa hoi. hieu he nam thuc va lang di cuu tre*.