Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
nam thuc » nam thuoc, am thuc, nam thu
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
te sach » toc sach
ky dung » ly dung, ky dang, ky vung
hieu ve » hieu va, hieu van
va hoa » van hoa, va hoc, ma hoa
va hoi » xa hoi, va hoc
ve nam » he nam, va nam, le nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dung ((va hoi) OR (va hoa)). hieu ve nam thuc va hanh vi ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dung ((va hoi) OR (va hoa)). hieu ve nam thuc va hanh vi ((cua tre) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dung ((va hoi) OR (va hoa)). hieu ve nam thuc va hanh vi ((cua tre) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: te sach ky dung ((va hoi) OR (va hoa)). hieu ve nam thuc va hanh vi ((cua tre) or (su triet))*.