Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
va tich » va tinh, va dich
coc tuc » coc luc, hoc thuc, doc thuc
hieu va » lieu va, hieu qua
hieu ve » hieu van
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
tuc va » thuc va, truc va, tuc xa
va cua » va chua, via cua, ma cua
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky lang xa hoi. ((hieu ve) or (hieu va)) coc tuc va tich ((va cua) OR (ca cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang xa hoi. ((hieu ve) OR (hieu va)) coc tuc va tich ((va cua) OR (ca cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang xa hoi. ((hieu ve) or (hieu va)) coc tuc va tich ((va cua) OR (ca cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang xa hoi. ((hieu ve) or (hieu va)) coc tuc va tich ((va cua) OR (ca cua)) tre*.