Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
day hang » dat hang, dai hang, day nang
so sach » so sanh, bo sach, co sach
nang xa » nang x, lang xa, nang ma
hang di » hang doi, hang vi, hang dien
he nam » nghe nam
di cau » da cau, diem cau

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