I have the same issue of the search function not working in Evernote with a basic account. I'm running Sierra 10.12.6 and Evernote 7.0.3. I tried what DTLow suggested. The first one (incomplete database) didn't fix the issue, but #2 Recreating Full Text Search Index seems to be doing the trick. Thanks!
I upgraded Evernote to Version 6.13.3 (455969 Direct) last night and I logged out and in and I am having the same issue. I get no results when I do searches.