Perhaps you should try some spelling variations:
"so sach tren phuong trinh khoa kham thong" » "so sach tren chuong trinh khoa kham thong", "so sach tren cong trinh khoa kham thong", "so sach tren huong tran khoa kham thong", "so sach trien phuong trinh khoa kham thong", "so sach tran phuong trinh khoa kham thong", "so sach ren phuong trinh khoa kham thong", "so sach tren phuong trinh hoa kham thong", "so sach tren phuong sinh khoa kham thong", "so sach tren phuong trinh hoi kham thong", "so sach tren phuong trinh khoa khap thong", "so sach tren phuong trinh khoa khau thong", "so sach tren phuong trinh khoa pham thuong", "so sach tranh phuong trinh khoa kham thong", "so sach tren phuong trinh kho khan thong", "so sach tren phuong trinh khoa than thong", "so sanh tren phuong trinh khoa kham thong", "bo sach tren phuong trinh khoa kham thong", "co sach tren phuong trinh khoa kham thong"
"thu sach tien hoc ba khoa phau thong" » "thu sach tien hoc ba khoa phap thong", "thu sach tien hoc ba khoa khau thong", "thu sach tien hoc ba khoa phan thong", "thu sach thieu hoc ba khoa phau thong", "thu sach tien hoc ba hoa phan thong", "thu sach tien hoc ba khoa than thong", "thu sach tien hoc ba khoa thu thong", "tu sach tien hoc ba khoa phau thong", "thuat sach tien hoc ba khoa phau thong", "thuoc sach tien hoc ba khoa phau thong", "thu sach tin hoc ba khoa phau thong", "thu sach tien hoa ba khoa phau thong", "thu sach dien hoc ba khoa phau thong", "thu sach tien hoc bia khoa phau thong", "thu sach tien hoc bao khoa phau thong", "thu sach tien hoc da khoa phau thong", "thu sach tien hoc bai khoa phau thong", "thu sach tien hoc ban khoa phau thong"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("so sach tren phuong trinh khoa kham thong") or ("thu sach tien hoc ba khoa phau thong"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so sach tren phuong trinh khoa kham thong") OR ("thu sach tien hoc ba khoa phau thong")).
• Removing quotes may allow a broader search: (( so sach tren phuong trinh khoa kham thong ) or ( thu sach tien hoc ba khoa phau thong )).
• Adding a wildcard symbol may retrieve word variants: (("so sach tren phuong trinh khoa kham thong") or ("thu sach tien hoc ba khoa phau thong"))*.