Perhaps you should try some spelling variations:
thanh hoi » thanh hoai, thanh hoa, thanh hai
thu sach » thuat sach, thuoc sach, thu hoach
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
hoi cua » hoi chuc
cao duc » dao duc, cao suc, giao duc
van cao » van dao, van bao, van hao
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi

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) OR (thu sach)) _ sang ((ma hoi) or (mai hoi)). hieu van cao duc va thanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) _ sang ((ma hoi) OR (mai hoi)). hieu van cao duc va thanh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) _ sang ((ma hoi) or (mai hoi)). hieu van cao duc va thanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) _ sang ((ma hoi) or (mai hoi)). hieu van cao duc va thanh hoi cua tre*.