Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
thu sach » tu sach, thuat sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty hang » ly hang, ty xang, thi hang
hieu va » lieu va, hieu qua
cao loc » cao hoc, cao toc, cao oc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
co hoi » co loi
va cao » va cac, va co, va dao
loc va » hoc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty hang ((co hoi) or (co hoc)). hieu va cao loc va hanh vi ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty hang ((co hoi) OR (co hoc)). hieu va cao loc va hanh vi ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty hang ((co hoi) or (co hoc)). hieu va cao loc va hanh vi ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: thu sach ty hang ((co hoi) or (co hoc)). hieu va cao loc va hanh vi ((cua tre) OR (cua triet))*.