Perhaps you should try some spelling variations:
su sach » so sach, vu sach
nang xa » lang xa, nang ma, mang xa
han tai » hang tai, nhan tai, van tai
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
luc va » duc va, tuc va, loc va
va cao » va cac, va co, va dao
xuc va » duc va, tuc va, xac va
tai va » thai va, mai va, tri va
thiet » thieu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (nang x)) hoi. hieu va cao ((xuc va) OR (luc va)) han tai va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang xa) or (nang x)) hoi. hieu va cao ((xuc va) OR (luc va)) han tai va thiet~".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang xa) or (nang x)) hoi. hieu va cao ((xuc va) OR (luc va)) han tai va thiet*.