Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
mang xa » lang xa, mang may, dang xay
hieu va » lieu va, hieu qua
va cau » van cau, va cac, va dau
xuc va » duc va, luc va, xac va
y mang » cay mang
tuc va » thuc va, truc va, tuc xa
vi dau » va dau, bi dau, ve dau
vi dai » si dai, li dai, vien dai

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 mang xa hoi. hieu va cau ((xuc va) or (tuc va)) hanh ((vi dau) OR (vi dai)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y mang xa hoi. hieu va cau ((xuc va) OR (tuc va)) hanh ((vi dau) OR (vi dai)) tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y mang xa hoi. hieu va cau ((xuc va) or (tuc va)) hanh ((vi dau) OR (vi dai)) tren*".