Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam tu
cua viet » ca viet, hoa viet, cua vat
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
ty tang » tay tang, ty xang, ty hang
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
me hoi » le hoi
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ty tang ((me hoi) or (xa hoi)). hieu ve ((nam thuc) or (nam thu)) va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty tang ((me hoi) OR (xa hoi)). hieu ve ((nam thuc) OR (nam thu)) va hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: vu sach ty tang ((me hoi) or (xa hoi)). hieu ve ((nam thuc) or (nam thu)) va hanh vi cua viet*.