Back issues of the National Library can be scanned by mobile phone. Many national libraries have begun to use digital technology to preserve and display their collections. Now, many libraries have begun to convert their books into digital format, so that people can access them through the Internet. Therefore, the problem of mobile phone flyback is possible. But the specific operation depends on the specific library policies and technical facilities. I suggest you consult the staff of the National Library, who will provide you with more specific information and guidance.