China HowNet: China HowNet is a professional literature database for a fee, providing a large number of academic papers and periodical articles. It is rich in content and covers books and documents in some professional fields well.
Superstar Digital Library: Superstar Digital Library is a free digital library, providing a large number of professional books and periodicals. Its literature is rich, covering books and materials in some professional fields.
Reading Show: Reading Show is a free e-book platform, which provides a large number of professional books and classic literature. Rich in content, many books are free.
Academic document service platform: Academic document service platform is a platform for providing academic papers and periodical articles, through which you can find and obtain some professional books and documents.
These platforms and software are important channels for providing professional books and documents. You can choose the platform and software suitable for your reading according to your own needs. I hope my answer can help you.