For historical research, I recommend the free and open source software, Zotero. It works best with secondary sources, but with additional manual entry, can also be used for manuscripts, newspaper articles, and other primary sources as well. 

Zotero

One way to keep track of databases and successful searches is to use a research log. Attached is a sample of what this might look like for you. 

Library subscription databases usually have a way to save searches in a personal account, or to export them by email, google drive, evernote, etc.

Our library subscriptions do not require a personal account, and are only suggested if you want to use their online saving tools; otherwise, try to export or save your searches and documents in another format.