Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
qua cham » qua hai, qua cac, va cham
mai hoi » mai khoi, dai hoi, lai hoi
sach uu » sach luu, sach tu, sach xu
uu wang » yu wang, cuu nang, huu bang
hanh va » hang va, hanh vi
so sach » so sanh, bo sach, co sach
loc va » luc va
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach uu wang ((mai hoi) or (ma hoa)). hieu qua cham ((loc va) OR (hoc va)) hanh va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach uu wang ((mai hoi) OR (ma hoa)). hieu qua cham ((loc va) OR (hoc va)) hanh va cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach uu wang ((mai hoi) or (ma hoa)). hieu qua cham ((loc va) OR (hoc va)) hanh va cua viet".
• Adding a wildcard symbol may retrieve word variants: so sach uu wang ((mai hoi) or (ma hoa)). hieu qua cham ((loc va) OR (hoc va)) hanh va cua viet*.