Perhaps you should try some spelling variations:
dai thuc » dan thuc, dai thu, dai thua
nam thuc » nam thuoc, am thuc, nam thu
ban hanh » ban hang
su triet » su viet, su tien, ve triet
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty dang » ty xang, ky dang, ty hang
dang xa » dang xay, lang xa, dang ha
hieu ve » hieu va, hieu van

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 dang xa hoi. hieu ve ((dai thuc) or (nam thuc)) ban hanh vi ((su triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty dang xa hoi. hieu ve ((dai thuc) OR (nam thuc)) ban hanh vi ((su triet) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty dang xa hoi. hieu ve ((dai thuc) or (nam thuc)) ban hanh vi ((su triet) or (cua viet))*.