This site lets you use a Bookworm database to read Obama's State of the Union in the context of all the other State of the Union messages given by American presidents. For any word in the message, just click on the text: the word will turn red. If you want to search a two-word phrase, just highlight both words. (You can't search for phrases longer than two words).
If you then click on a bar, you'll get an (ugly, unformatted, alas) list of all the times that President used the phrase. Certain forms of punctuation (hyphenated words, etc.) won't work quite right yet. Keep in mind that the State of the Union has changed a lot in its history. Of particular importance to understanding these charts is knowing that it was written, not spoken, before Woodrow Wilson. You're looking at the address: change that dropdown to use any other year as a baseline.
Also, check out the two pieces Mitch Fraas and I wrote for the Atlantic on the language of past State of the Unions and the locations mentioned in past speeches. I owe the idea for this layout to Yoni Appelbaum and John Gould at the Atlantic. The text of the speeches is from the American Presidency project at UCSB, except for the 2015 text which I took from the White House's post at Medium.