The best that you can do is pull up the list of the last 250 torrents that you have downloaded. You can do this by clicking [you] in the top left corner of the page, then scrolling down to the bottom and click the "Show Completed Torrents" link.
There is of course another possible way to get more than the last 250 torrents. There's a bit of a cheater's trick. Click the "Search" button at the top of the page, then click the "Show Torrents not yet voted", and the last 250 torrents that you have not voted on will appear. The difference here is that the database will maintain the list of ALL the torrents that you have downloaded, but have not yet voted for, which is separate from the rest of the history.
The catch here is that once you have voted for all of your torrents, you will no longer be able to use this feature for previous torrents, but rather, only future torrents that you download from this point forward.
Hope this helps. 🙂