Perhaps you should try some spelling variations:
sach tren » sach tien, sach tranh
tren thuc » trien thuc, tron thuc, trinh thuc
sach thai » sach tham, sac thai, sach tai
thai thuc » thai thuy, thai tuc, tham thuc
thuc banh » thuc hanh, thuc ban, thuc thanh
thuc cac » thuc cach, tuc cac, phuc cac
cac khoa » cac khoan, cac khoi, dac khoa
toc sach » hoc sach, doc sach, thuoc sach
banh chi » danh cho, dinh chi, bao chi
so sach » so sanh, bo sach, co sach
khoa he » hoa he, khoa hoc, khong he
chi pho » chi phi, chi khoa, chi phan

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: (( so sach tren thuc cac khoa he thong ) OR ( toc sach thai thuc banh chi pho thong ))~.
• Adding a wildcard symbol may retrieve word variants: (( so sach tren thuc cac khoa he thong ) or ( toc sach thai thuc banh chi pho thong ))*.