Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
thuc day » thuc dan, thuc vat
danh vai » danh sai, danh va, doanh van
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan
tu sach » thu sach, su sach, te sach
va lam » van lam, va lap
co hoi » co hoc, co loi
vai va » mai va, dai va, hai va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty xang) OR (ky nang)) co hoi. hieu va lam ((thuc va) OR (thuc day)) danh vai va triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty xang) or (ky nang)) co hoi. hieu va lam ((thuc va) OR (thuc day)) danh vai va triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty xang) or (ky nang)) co hoi. hieu va lam ((thuc va) OR (thuc day)) danh vai va triet*.