If they were trying to steal the whole car they would probably go through the window/door. Going through the hood makes me think they're after your parts. If they have been to your car more than once they'll probably be there again. I recommend a car alarm that is sensitive enough to know when someone's prying the hood open or breaking a window. I'm surprised they haven't broken a window and used the hood popper by now. That might be next on their list, but these guys sound pretty stupid.
Pick a night to watch the car all night. Hide out of sight with a bright spotlight and a hose with a high pressure nozzle. When you see them prying at your car turn the spotlight on their face so they still can't see your identity and spray them with freezing cold hosewater. They will be startled, cold and wet. For all they know there's a big angry man hiding behond that spotlight. They'll probably run off, but have backup with you in case they don't. I think it's safe to say you're not dealing with a professional thief.
If you live in an apartment complex tell the office they need better security for the parking lot at night. If you're going to electrify your car like that other person suggested, maybe put a sign in the window as fair warning so an innocent person doesn't accidentally brush against your car and get electrocuted. If you're in an apartment complex electrifying your car probably isn't the best idea. Your neighbors could get zapped bringing in groceries from their car, and that wouldn't be nice.
If your car is an old jalopy like my old Honda was, and you're not worried about the body condition you can get a metal plate as long as that side of the hood and bolt or JB Weld it to the hood, covering the gap so there's nowhere on that side to wedge a crowbar. Don't JB Weld the hood shut or you won't be able to feed your car oil and other important things like that. JB Weld can be found at most car part stores, it's really easy to use, has many creative uses and it's like glue made out of metal. Be sure to allow plenty of time for the stuff to dry before the next time you drive.