first of all, the way you are calling is wrong, your url should be like this https://api.twitter.com/1.1/search/tweets.json?q=zkalvi.
By this url you will get following output
{"errors":[{"message":"Bad Authentication data","code":215}]}
This is because , in twitter 1.1 version, most of thing needs authentication. So better you use twitter server side library for getting results.
Here is link for twitteroauth library for php twitteroauth