Unison does not include any built-in Usenet searching functionality (except within messages you have already read). However, Unison does provide an easy way to access external web sites which allow you to search all of Usenet.
To add a Usenet search site to Unison:
Search sites that you have set up in Unison's preferences will appear in the Search section of the source list:
Click on the Search section header to open it, then click on a search site to view it.
Each search site works a bit differently, but most offer their results as a downloadable NZB file. NZB files identify the specific Usenet posts that contain the file you wish to download.
If you click on an NZB download link from a search site, Unison will automatically try to locate and download the files referenced within it. Downloads can be monitored from the Transfers section of the source list.
To remove a Usenet search site from Unison: