"東京大学で利用できる電子ブック"
"e-books held in University of Tokyo"
https://www.lib.u-tokyo.ac.jp/ja/library/contents/ebook
https://www.lib.u-tokyo.ac.jp/en/library/contents/ebook

The above sites will be closed at the end of December 2024. It will also be removed from the Database List. You can find eBooks through E-journal & E-book Portal.