Perhaps you should try some spelling variations:
thanh va » thanh van, hanh va, thanh ha
thu sach » thuat sach, thuoc sach, thu hoach
va thanh » gia thanh, ban thanh, va tinh
tu sach » su sach, te sach, tu cach
cao duc » dao duc, cao suc, giao duc
cam duc » cam xuc, pham duc, nam duoc
hieu ve » hieu va, hieu van
ty hang » ly hang, ty xang, thi hang
cua tre » cua te, cuu tre, cua triet
hang x » nang x, hoang xa, chang xu
va cua » va chua, via cua, ca cua
x hoi » xa hoi, o hoi, x ho

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)) ty hang x hoi. hieu ve ((cam duc) OR (cao duc)) va thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty hang x hoi. hieu ve ((cam duc) OR (cao duc)) va thanh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ty hang x hoi. hieu ve ((cam duc) OR (cao duc)) va thanh va cua tre*".