Yes, you can search URL fields, however, it is a bit different than searching content and other fields.
For example, if you index http://searchblox.zendesk.com, and you need to search the domain, you must provide the search term as follows:
The parent URL between http:// and / would be taken as a single term.
You can also give the full URL with special characters by enclosing the URL within double quotes:
Sub-paths can also be searched directly. For example, if you need to find whether the word "searching" is available in the subpaths
the query should be:
You can also combine queries using logical operators along with URL parameters as:
collection AND url: searching
To learn more on fielded searches read: Fielded Search in SearchBlox