Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
xuc ban » duc ban, quoc ban, xuat ban
hoi cua » hoi chuc
anh hoi » anh noi, anh hoc, anh khoa
cuc ban » cua ban, cac ban, cuu ban
qua cai » qua hai, qua cac, qua ca
hang xa » hoang xa, hang va, hang ca
ty hang » ly hang, ty xang, thi hang
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: ((tu sach) or (thu sach)) ty hang xa hoi. hieu qua cai ((xuc ban) OR (cuc ban)) anh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty hang xa hoi. hieu qua cai ((xuc ban) OR (cuc ban)) anh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ty hang xa hoi. hieu qua cai ((xuc ban) OR (cuc ban)) anh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty hang xa hoi. hieu qua cai ((xuc ban) OR (cuc ban)) anh hoi cua tre*.