After conducting a search on the ProQuest Platform, you will see a URL similar to this in your browser's address bar.  This is not a permalink that can be used to get back to the search results set:

https://0-search-proquest-com.library.cairn.edu/results/69AEE602C56243AFPQ/1?accountid=12345

In order to get a permalink, click Save search/alert -> Get search link



The resulting overlay window will have a permalink that can be used to navigate back to the search results. 



This type of link is good for 1 year.  If you need to save a search for a longer time period, you will want to create a My Research account and save your search there.