#Firefox address bar modifiers:
^ to search your browsing history.
* to search in bookmarks.
+ to search in pages you've tagged.
% to search in your currently open tabs.
# to search in page titles.
$ to search in web addresses (URLs).
? to search for matches in suggestions.
Example: search for word headphones in your bookmarks only type on the address bar:
*headphones
And, if you want to include only the results of your browsing history it would be:
^headphones