Perhaps you should try some spelling variations:
va triet » va trien, ve triet, cua triet
vanh dai » van dai, vanh tai, lanh dao
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va vanh » va van, va danh, va hanh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
ca viet » va viet, co viet, hoa viet
nang o » nang co, nang ho, nang ro
ve am » va am
o hoi » co hoi, o hoc, o hai

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 ky nang o hoi. hieu ve am thuc va vanh dai ((((va triet) OR (va thiet))) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. hieu ve am thuc va vanh dai ((((va triet) OR (va thiet))) OR (ca viet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoi. hieu ve am thuc va vanh dai ((((va triet) OR (va thiet))) or (ca viet))*".