Most databases allow you to go back to previous searches that you have run in your current login session.
You can see these searches and go back to the results, but you can usually also do things such as edit a search and combine searches.
For details of how you can access Search History in the main database platforms, see Databases and Database Platforms.
Here is what the EBSCOhost Search History looks like:
Your Search History will be cleared when you log out of a database. If you want to save searches permanently, you need to create a personal account/folder within that database or database platform. You can find out how to do that from the help screens of the database or platform you are using.