Perhaps you should try some spelling variations:
sach doi » sach hoi, sach moi, sach dao
hieu van » hieu va, thien van, lieu va
va thanh » ban thanh, va tinh, le thanh
sach ty » sach y, sach tu, sach thu
hang xa » hoang xa, hang va, hang ca
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ty) or (sach doi)) hang xa hoi. hieu van cam xuc ((va thanh) OR (gia thanh)) tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach doi)) hang xa hoi. hieu van cam xuc ((va thanh) OR (gia thanh)) tri cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) or (sach doi)) hang xa hoi. hieu van cam xuc ((va thanh) OR (gia thanh)) tri cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) or (sach doi)) hang xa hoi. hieu van cam xuc ((va thanh) OR (gia thanh)) tri cua tre*.