Perhaps you should try some spelling variations:
phap thong » phap phong, phap chong, pho thong
sach tien » sach tren, sach thieu
tien thuc » trien thuc, kien thuc, bien thuc
cac khong » cac phong, cat khong, cac phuong
thuc hang » thuc hanh, thu hang, phuc hang
hang khoa » dung khoa
khoa phap » khoa phau, khoan phai, khong phap
thuc cac » thuc cach, tuc cac, phuc cac
khong he » khong khi, hong ha, khong _
sach bai » sach dao, cac bai, sach xa
bai thuc » bai thuoc, bao thuc, dai thuc
so sach » so sanh, bo sach, co sach
tu sach » thu sach, su sach, te sach

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 tien thuc cac khong he thong ) OR ( tu sach bai thuc hang khoa phap thong ))~.
• Adding a wildcard symbol may retrieve word variants: (( so sach tien thuc cac khong he thong ) or ( tu sach bai thuc hang khoa phap thong ))*.