If you want to indicate that a specific word or phrase is REQUIRED in search results, how can you do

Put it in quotes.

You can search for "google advanced" or "google settings" to see what else it can do for you. For instance you can search a specific web site; you can search for a specific filetype. You can use images.google.com to search for a picture that looks like one you have. Then there is video.google.com which indexes much more than just youtube.

100 search engines: www.distancedegrees.com/2008/lose-your-wikipedia-crutch-100-places-to-go-for-good-answers-online/
Google tricks: www.johntedesco.net/blog/2012/06/21/how-to-solve-impossible-problems-daniel-russells-awesome-google-search-techniques/
Google advanced: iwastesomuchtime.com/on/?i=20501