Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
lam thuc » lam thuoc, am thuc, nam thuc
sach ty » sach y, sach tu, sach thu
dan hai » doan hai, dang hai, dan khai
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
va dan » ca dan, va dao, va dau
va lam » van lam, va lap
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 ty hang ((x hoi) or (o hoi)). hieu va lam thuc va dan hai ((cua triet) OR (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty hang ((x hoi) OR (o hoi)). hieu va lam thuc va dan hai ((cua triet) OR (va triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty hang ((x hoi) or (o hoi)). hieu va lam thuc va dan hai ((cua triet) OR (va triet))*".