For each book, there is a limit on the number of pages that can be copied, printed, and page/chapter-downloaded per user, per day.

For a user signed in to an Ebook Central account, the default limits within Ebook Central are as follows:
For books that are full-downloaded:
The limits and the pages remaining for each of the above are shown on each book's Detail Page.  To see this information while reading a book, click User-added image "Book Details" on the side bar to display the details in the left panel.
User-added image