[Delk]

You can still protect your artillery, although it's more complicated. You may need to position melee units tactically so that they and their zones of control [0] prevent enemy units from easily (and quickly, during a single turn) reaching your artillery units. Using terrain tactically not just to get a defensive edge in combat strength but also to make your ranged units less easily reachable to enemy melee units may also become even more important.

What I find most difficult about protecting your artillery in Civ 5 is attempting to siege cities with units that have a range of 2, because they'll be vulnerable to bombardment from the city no matter what.

But yeah, the artillery is more vulnerable in Civ 5. You can counteract some of that.

[0] https://civilization.fandom.com/wiki/Zone_of_control_(Civ5)