I have no ideas what search you speak of, since Unity has a LOT of different ways to search stuff.
REGARDLESS of what window you are talking about, please consider using source control in order to guard and protect your hard-earned work.
Personally I use git because it is free and there are tons of tutorials out there to help you set it up.
Here’s how I use git in one of my games, Jetpack Kurt:
Using fine-grained source control as you work to refine your engineering:
Share/Sharing source code between projects:
Setting up the right .gitignore file:
You wouldn’t play a 1000-hr RPG without a savegame… don’t work on a game for 1000 hrs without source control!