I can only answer your second question - i.e. if anything can be done to resurrect these files. As others have mentioned, that uncorrupted version you're seeing briefly as you import them into Lightroom is the preview JPEG generated in-camera when you shoot RAW. There are plenty of tools that will recover those previews for you, hopefully even if the RAW file itself is corrupted. (The fact that you're seeing the previews in other software is an encouraging sign.)

Check this accepted answer for a list of software. I've tried dcraw and it worked a treat.

Good luck!

I can only answer your second question - i.e. if anything can be done to resurrect these files. As others have mentioned, that uncorrupted version you're seeing briefly as you import them into Lightroom is the preview JPEG generated in-camera when you shoot RAW. There are plenty of tools that will recover those previews for you, hopefully even if the RAW file itself is corrupted. (The fact that you're seeing the previews in other software is an encouraging sign.)

Check this accepted answer for a list of software. I've tried dcraw and it worked a treat.

Good luck!