Perhaps you should try some spelling variations:
doanh cua » doanh luan
va triet » va thiet, va trien, ve triet
va doanh » van doanh, vay doanh, va danh
nang co » nang doc, nang noi, nang hoc
hieu ve » hieu va, hieu van
cam luc » cam xuc, cau luc
co sach » bo sach, cuon sach, hoc sach
so sach » so sanh, bo sach, hoc sach
ve cam » ve cham, ve cac, va cam
luc va » duc va, tuc va, loc va
cua va » cua vat, chua va, cua van

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

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