Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
danh va » doanh va, hanh va, anh va
y nang » ly nang, v nang, may nang
ve cac » va cac, vien cac
he va » che va, he van, te va

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

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