See which ones really relate and go together. You can always use just part of one article if that works for your thesis. For myself, I love to write ebook titles that are theses–with the benefits and preferred audience in them.
Turn your long blog articles into a shorter ebook. I still write some posts at 1100-1600 words or more. These, with more specific, details will especially work to become a shorter ebook of 7-10 pages.
If you have a blog, you've got an ebook goldmine.