Backlinks and their reach...

I've been working on an authority site now with close to 60 pages. Only starting around page 40 did I begin targeting keywords and working with keyword density and all that, because I had articles written from previous years before I knew about SEO. I've been studying and learning, and now that some time has passed I'm seeing the importance of promotion.

I see now that you can't just throw up some articles and hope people will magically find them. I've got a few lucky ones that ranked well for some reason, and I've started backlinking to them using article directories. I'm using one link to the article itself, and one link to the main site.

So say I build up the strength of the main site by backlinking a ton to the home page. Does that at all lend any strength to the ranking of the internal pages? Or do I really have to attempt to build back links to 100's of pages each individually? I would think the internal pages gain something from the strength of the main page, but I'm just guessing. Do you guys know?