Perhaps you should try some spelling variations:
hieu va » lieu va, hieu qua
han tai » hang tai, nhan tai, van tai
sach tu » sach thu, cach tu, sach uu
nang xa » lang xa, nang ma, mang xa
cao luc » bao luc, cao duc, cao suc
sach ty » sach y, sach thu, xach tay
va han » va phan, van han, va hanh
luc va » duc va, tuc va, loc va
tai va » thai va, mai va, tri va
va cao » va cac, va co, va dao
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) OR (sach tu)) ((nang xa) OR (nang x)) hoi. hieu va cao luc va han tai va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach tu)) ((nang xa) or (nang x)) hoi. hieu va cao luc va han tai va thiet~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach tu)) ((nang xa) or (nang x)) hoi. hieu va cao luc va han tai va thiet*.