Perhaps you should try some spelling variations:
te sach » toc sach
cua hoi » cua moi
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
va dinh » van dinh, va kinh, va tinh
y hang » ly hang, ty hang, yu hang
va cam » va cham, va cac, va cao
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 y hang ((xa hoi) or (cua hoi)). hieu va cam duc va dinh ((vi cua) OR (di cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y hang ((xa hoi) OR (cua hoi)). hieu va cam duc va dinh ((vi cua) OR (di cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y hang ((xa hoi) or (cua hoi)). hieu va cam duc va dinh ((vi cua) OR (di cua)) triet".
• Adding a wildcard symbol may retrieve word variants: te sach y hang ((xa hoi) or (cua hoi)). hieu va cam duc va dinh ((vi cua) OR (di cua)) triet*.