Perhaps you should try some spelling variations:
thanh va » thanh van, hanh va, thanh ha
sach ty » sach tu, sach thu, xach tay
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
duc gia » quoc gia
va chua » vua chua, ca chua, va chu
chua te » cua te, chua tu, chua xe
va cao » va cac, va co, va dao
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ty) or (sach y)) nang ((x hoi) OR (xa hoi)). hieu va cao duc gia thanh va chua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sach y)) nang ((x hoi) OR (xa hoi)). hieu va cao duc gia thanh va chua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ty) or (sach y)) nang ((x hoi) OR (xa hoi)). hieu va cao duc gia thanh va chua te".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) or (sach y)) nang ((x hoi) OR (xa hoi)). hieu va cao duc gia thanh va chua te*.