Introduction
There are a number of ways to find or look for variables or questions to use in your analysis from either the Outputs tab or the Variables and Questions tab.
Quicksearch
In the Outputs tab, Quicksearch is enabled in drop-down menus, so that when you type some characters, the menu is shortened to only show you options containing those characters. For example, if you start typing some characters in the blue drop-down box the results will be restricted to the characters entered:
Find
The Variables and Questions tab and the various dialog boxes for creating variables, such as Binary - Complicated Filter and JavaScript Variables, have a Find box:
It is used by entering the letters to be searched for and pressing the magnifying glass 
until the desired variable or question is found.
When creating variables, the Sort variables alphabetically button
can be used to sort lists alphabetically to assist in finding variables and questions of interest.
See Also
How to Use JavaScript to Search Text for Keywords
How to Use Search/Replace to Conditionally Recode Lots of Variables