Perhaps you should try some spelling variations:
thanh hoi » thanh hoai, thanh hoa, thanh hai
sach thu » sach thue, sach thieu, sach tham
va thanh » gia thanh, ban thanh, va tinh
sach ty » sach y, sach tu, xach tay
nang xa » nang x, lang xa, nang ma
van cam » van lam, van cau, van dam
hoi cua » hoi chuc
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 thu)) nang xa hoi. hieu ((van cam) or (van nam)) duc va thanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) nang xa hoi. hieu ((van cam) OR (van nam)) duc va thanh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) nang xa hoi. hieu ((van cam) or (van nam)) duc va thanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) nang xa hoi. hieu ((van cam) or (van nam)) duc va thanh hoi cua tre*.