Perhaps you should try some spelling variations:
giai toan » giai doan, giai toa, gioi toan
con thong » cong thong, con hong, cong thuong
giao con » giao cong, gian con, gia cong
te sach » toc sach
co giao » cho giao, so giao, bo giao
so sach » so sanh, bo sach, co sach
ve giai » va giai, ve giao, de giai
nha co » nha cao, nhan co, nhat co
nha ve » nhat ve, nhan ve, nha va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach nha co giao con thong tin ) OR ( so sach nha ve giai toan thong tin ))~.
• Adding a wildcard symbol may retrieve word variants: (( te sach nha co giao con thong tin ) or ( so sach nha ve giai toan thong tin ))*.