Evernote won’t let you search for “#hashtag”, it ignores the “#” character. This is apparently an integral part of its search grammar, it treats punctuation as spaces. Or something. Anyway: I had several notes with both “#documentation” and “documentation”. I couldn’t find the former without also finding the latter. (I didn’t realize this when I was tagging things with “#documentation” or I’d’ve done it differently. I’ve also tagged many other items with internal hashtags.)
Chrome has no such limitation, thank $DEITY.
So I did the seach for “documentation”, selected all those notes, exported them as a single HTML file, opened the note in Chrome (something EN helpfully offers to do for you at the end of the export), and now I can find all my #documentation tags.
It’s not great, but it’s not terrible, either.
Hope this helps.
Update 4/9/14: Minor edits to the above, and this: After trying a couple of different things, using a QQ suffix seems to work. I tried _documentation, which doesn’t suck, and EN will find it, but it doesn’t match a plain search for “documentation”, and I’d rather not duplicate all my inline tags (e.g. “… add this to the documentation _documentation”).
If you have “documentationQQ” then searching for “documentation” finds it, as well as searching for “documentationQQ”, which finds only the tags. And “QQ” kinda sorta looks like eyeballs, and regardless is a clear tag (ha) that “this is something different …”.