Dupefree Pro is a free software which you can download at http://dupefreepro.com. I have found two uses of this software, one being able to compare two content to detect any similarities (good for checking original from rewritten) and finding LSI keywords for your content. 

Finding duplicated content using this software is relatively easy. You just copy paste your original and rewritten article on the provided space, hit the COMPARE button and in seconds,Dupefree Pro will highlight all the keyword phrases on both ends with similarities.

Aside from that, Dupfree Pro can also check the article for online similarities though way behind from the service of copyscape. My last testing of finding exact phrases were unsuccessful since it returned several million results when in fact when searched on Google doesn't find anything.

What I love about Dupfree Pro is it's ability to give off LSI keywords. The process is fairly simple too. Just enter your base keyword, hit the LSI button and in seconds you will have an entire new LSI list in front of you. 

While DupeFree Pro gives limited information about LSI keywords, it is still one of the best tools I've came across.