The typical search session involves working several different search interfaces or gateways and trying differents sets or combinations of keywords. Very quickly the researcher can lose track of what had been tried and what worked or didn't work. Here are a couple methods of tracking your search histories. You can also use your browser's "history" feature to go back to find a site you visited; sometimes a particular search text and parameters are retained in the url.
Use your preferred note-taking software (e.g., Word, Google Docs, Evernote) to record in shorthand the searches. In the example below the ">" symbol represents click steps in the respective interfaces and search strings are enclosed in quotation marks. Sometimes your search is embedded in a reproducible url and you can copy/paste it as a link as in the Google Scholar search link below.
Here is an example of journal entries for session in which searches were conducted on the same topic:
Advantages: searches are logged automatically.
Services that offer accounts with logging feature: