what is the best way to find the full transcripts of speeches by presidents? is there a site that you use for that sort of research?

Yes, there are two particular sites that I tend to use whenever I'm researching speeches or Presidential messages and they are both excellent sources.

The American Presidency Project at the University of California, Santa Barbara is an invaluable resource. The UCSB site has archived hundreds of thousands of speeches, press conference transcripts, messages, and declarations from every President in American history. It's amazing how much information they have available for researchers, and how easy they've made it to navigate the site and find specific speeches or documents. As an example, f you felt like finding the transcripts for the 200+ press conferences that Herbert Hoover did while he was in office, UCSB's American President Project has them ready for your reading pleasure. And they don't just provide easy access to the major speeches that Presidents made while in the White House. You can find transcripts of quick remarks that Presidents made from train platforms during whistle-stop campaigns or radio addresses or signing statements. It's really an indispensable resource for researchers of the Presidency.

The Miller Center at the University of Virginia also has an incredibly useful website with archives of Presidential speeches, but also in-depth essays and features about the Presidency and each of the Presidents. There are extensive oral histories on Presidents dating back to Jimmy Carter, with fascinating insight from scores of people. And the Miller Center has also created a site within their website focusing on the tapes from the White House recording system that eventually helped bring down Richard Nixon. Nixon wasn't the only President who secretly recorded conversations in the White House, and there are tapes available from Franklin D. Roosevelt, Harry Truman, Dwight Eisenhower, John F. Kennedy, and Lyndon B. Johnson, as well as Nixon. Instead of having to search for those recordings at each of those Presidents' respective Presidential Libraries, the Miller Center has made it possible to search their archives for all of those Presidential Recordings. In most cases, they've also helpfully provided transcripts as the tapes are frequently difficult to clearly understand.

Those two sites are pretty much perfect for Presidential history researchers, particularly if you're seeking transcripts of speeches or Presidential messages. I'd also strongly recommend checking out the Presidential Library websites if you're researching someone who has a library. In my opinion, the Presidential Library system is one of the treasures of the National Archives and a treasury of research potential. Almost all of the 15 Presidential Libraries in the network officially maintained and operated by the NARA have extensive research materials that can be accessed online.