Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va cham » va chat, va tham
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
y hang » ly hang, ty hang, yu hang
cham o » cham soc
o va » do va, so va, co va

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 y hang ((mai hoi) or (ma hoa)). hieu va cham o va hanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y hang ((mai hoi) OR (ma hoa)). hieu va cham o va hanh va su triet.
• Adding a wildcard symbol may retrieve word variants: tu sach y hang ((mai hoi) or (ma hoa)). hieu va cham o va hanh va su triet*.