Some eBook platforms restrict the number of days (if any) an eBook title can be downloaded for, but in general the time allowed is between 4 and 7 days. As we may be expecting a higher than normal usage of eBooks, please either return the downloaded eBook when you have finished with it or read the book in a browser window.
Many publisher sites such as Cambridge, Springer and Wiley allow you to download and save individual chapters as PDF documents.