In many library databases the URL that appears in your browser's address bar is not a persistent or permanent URL. The URL includes session information specific to your search and will expire in a short time.
Here is an expired URL to a search results page in an EBSCO database:
https://web.a.ebscohost.com/ehost/resultsadvanced?vid=2&sid=8a1f8e33-f9a4-43e1-bd9a-2df3383190a1%40sessionmgr4006&bquery=test&bdata=JmRiPWE5aCZ0eXBlPTEmc2VhcmNoTW9kZT1TdGFuZGFyZCZzaXRlPWVob3N0LWxpdmUmc2NvcGU9c2l0ZQ%3d%3d
Here is a permalink to the same search results page:
The permalink differs in two ways from the expired URL: