When you perform a Google query, the links in the results page do not actually point to the pages you expect. Instead, they point to a Google server which logs which link you click and then redirects you to the actual page. They do this so that they can track the results (i.e., which of the results we found were actually desirable by the user?)
There is an easy fix however, just install a browser extension to override this tracking and make the links point to the actual pages/files. There are plenty available; just search for
Google tracking or something to that effect. Note however that not all will work correctly, so you may have to test a few. My personal recommendation is the googlePrivacy user-script. Not only does it work, but because it’s just a user-script instead of a full-fledge extension, it doesn’t use as much resources.
Now, whenever a Google search returns non-HTML results, you can simply right-click the link and select Save As or hold Alt (or ⌥ (Option) on Macs) and left-click it.