Perhaps you should try some spelling variations:
su triet » su viet, ve triet
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
truc va » thuc va, thuc vat, trung va
hang co » hang cho, hang ca, nang co
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
su tien » su kien, su hien, tu tieng
va cau » van cau, va cac, va dau
co hoi » co hoc, co loi

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 co hoi. hieu va cau ((truc va) or (hoc dan)) hanh vi ((su triet) or (su tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty hang co hoi. hieu va cau ((truc va) OR (hoc dan)) hanh vi ((su triet) OR (su tien)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty hang co hoi. hieu va cau ((truc va) or (hoc dan)) hanh vi ((su triet) or (su tien))*.