There are a few options, depending on how much work you want to do.
1. Use the Bing search app (easy but won't index the entire document)
You could use the Bing Search app to do this it won't return the entire document.
The following search would look for pastes that contain the work Splunk:
| bingsearch query="splunk site:pastebin.com" | table name displayUrl snippet
Here is what the results would look like:
2. Write a custom web-site scraper (harder, but can be made to do whatever you want)
You could write your own scripted input in Python using something like scrapy (https://scrapy.org/). This is more involved since you will need Python code but you can make this script do whatever you want.