How can I detect when a tweet is duplicated, the only way is to compare the text ?
Those are not duplicate Tweets - they are all independent, different Tweets with different IDs. The Tweet status text is duplicated, yes (probably someone is copy and pasting the status, or using an old-style “RT” format client). You’d have to filter those our in your own code.
If the tweet is a retweet you will have the retweeted_status property populated with the original tweet. Otherwise it is not a duplicate or as mentioned by andypiper it is probably a copy or RT formatted tweet.
I found it strange because I did a search with a size of 5 elements and the surprise was that everyone is equal to the naked eye. Excuse my english I am using translator.