Many of the search operators you use in Google's search box work in the new Google Reader search, and the Google Operating System weblog rounds them up along with a few other Reader search tips. For example:
2. Exact matches: put quotation marks around your search terms to get the results that include an exact phrase.
3. Wildcard: use an asterisk to replace some words in your query. This only works for exact matches. Include an asterisk for each word you want to replace.
For example: "has * * * new features" matches: "has just announced several new features", "has recently added two new features", "has released a few new features".
4. Negative searches: if you want all the posts that contain [book search]but don't include [Google] , search for [book search -Google] .
Unfortunately there don't seem to be any more specific operators yet (e.g., title:GTD), but the post highlights a few other great Google Reader tricks, like bookmarking common searches. Reader doesn't currently have a feature to create smart folders/bookmark searches (though that seems like a killer addition), but until it does—or until some intrepid coder (or reader, *wink wink*) puts together a simple Greasemonkey script—regular old bookmarks will have to do.