If you want to link to a particular database such as Academic Search Complete or JSTOR, do not grab a URL from the browser's address bar when you are in the database. Some databases redirect users to a session-specific page after authentication, so if you copy the URL from the browser's address bar after you're in, the URL will not work for others.
Instead, grab the link from the Research Databases page by right-clicking the database name and copying the URL.