Perhaps you should try some spelling variations:
tien thuoc » trien thuoc, tin thuoc, bien thuoc
thuoc sach » hoc sach, nuoc sach, thuat sach
sach trung » mach trung, sach thuong, sach dung
quoc doanh » quoc danh, quoc khanh, quoc toan
doanh khoa » toan khoa
sach tien » sach tren, sach thieu
sach nghe » sach nghiep, sach nha, anh nghe
pho thong » he thong
nghe pho » nghe cho, nghe phan, nghe khoa
khoa pho » khoa phu, khoa khoa, khoa phau
su sach » so sach, vu sach
tu sach » thu sach, te sach, tu cach

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 tien thuoc sach nghe pho thong ) or ( tu sach trung quoc doanh khoa pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tien thuoc sach nghe pho thong ) OR ( tu sach trung quoc doanh khoa pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( su sach tien thuoc sach nghe pho thong ) or ( tu sach trung quoc doanh khoa pho thong ))*.