Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
cua triet » cua viet, su triet, va triet
toc sach » hoc sach, doc sach, thuoc sach
toc sac » toc san, hoc sach, doc sach
hieu ve » hieu va, hieu van
ve nhan » ve nha, de nhan, va nhan
co hoi » co hoc, co loi
vat va » dat va
va dai » va dao, vi dai, va dau
o hoi » o hoc, o hai, o hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sac) OR (toc sach)) ky nang ((o hoi) or (co hoi)). hieu ve nhan thuc vat va dai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sac) OR (toc sach)) ky nang ((o hoi) OR (co hoi)). hieu ve nhan thuc vat va dai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sac) OR (toc sach)) ky nang ((o hoi) or (co hoi)). hieu ve nhan thuc vat va dai cua triet".
• Adding a wildcard symbol may retrieve word variants: ((toc sac) OR (toc sach)) ky nang ((o hoi) or (co hoi)). hieu ve nhan thuc vat va dai cua triet*.