I wish I knew a place where you could view old Mania Magazines in full... most of the ones from my childhood, including those covering childhood favorite themes, are either in extremely poor condition or missing entirely. Catalogs aren't such a problem for me since my dad was often wise enough to keep the catalogs from me when I was a kid, but I still like to look up online versions of catalogs from before my time as a LEGO fan, or from other countries which in some cases had different set names and story information for even the themes within my lifetime.
Brickset has an archive of Bricks & Pieces
magazines, the LEGO Club magazines from the UK in the '70s and '80s.
LEGO.com has a brief archive of LEGO Club Magazine
and LEGO Club Jr. Magazine
interactive samples from the past couple years, although it's not really kept up-to-date so some of the most recent magazines are absent. You can find the most recent magazines in an abridged, interactive form at the LEGO Club website
. A Google search at the host site for those interactive magazines (imc.ceros.com, imm-lite.ceros.com, or nxtbook.com) can bring up slightly less recent ones as well. Some of these, but not all of them, include an option to download PDF versions of the magazine samples, or even just specific pages.
The LEGO Club website used to have a "Magazine Flashback" which included abridged versions of various magazines throughout the years. That is no longer on the live site, but it can be found here
courtesy of the Wayback Machine.
For catalogs, Peeron is a good source but I should offer a warning that it will kick you out after viewing a certain number of pages due to an automatic feature meant to bots and web crawlers from slowing down the site. Another source I often use for old catalogs is Brickfactory.info
Hope some of these links help you!