What you will want to take a look as is generating a report using the business views feature of ALM. Here are a few steps to get you to your end goal.
From the Analysis module:
Click Add New Button and select New Business View Excel Report
Enter a name and click OK
Report is made with your name, and to right, there is Generate, New and Install Addin. Click on Install Addin
Should get message Excel Report Add-in has been successfully installed.
Now open MS Excel and there should be a HP ALM tab to the right
Click on the tab to load its menu options, and then click the Login button that is to the left
Pop up window will allow you login to ALM and your project
Once logged in, now click on the Add button to get the Add Worksheet window open
Here you have the Business Views available
Scroll down and look for Defects with No Linked_Req(Defect_With_No_LInked_Req
Select and and hit Ok
Now you have your full report which you can filter and edit as needed for your preferred data