Where can I find examples of the horrors of war, the effects of war on the soldier, and nationalism in All Quiet on the Western Front?

Chapter 6 in Remarque's work is a good place to find evidence of how World War I impacted the soldier.

Remarque shows the transformation of the soldier in World War I. One instance in chapter 6 where we can see the effects of war on the solider is when Paul writes about Himmelstoss's reaction to battle.  At a point where all of the soldiers leave the dug-out to participate in the conflict, Paul notices that Himmelstoss does not follow the others:

When we run out again, although I am very excited, I suddenly think: "Where's Himmelstoss?" Quickly I jump back into the dug-out and find him with a small scratch lying in a corner pretending to be wounded. His face looks sullen. He is in a panic; he is new to it too. But it makes me mad that the young recruits should be out there and he here. 

Himmelstoss's reaction to war is what makes him refuse to go out and fight. His "panic" and "sullen" appearance shows war's effect on him. He has become a shell of who he used to be. Paul's reaction is to beat him, another example of war's violent effect on the soldier.

As Paul continues to describe the fighting, he reveals the horrors of war. When Paul writes about war, he reveals its true nature:

We see men living with their skulls blown open; we see soldiers run with their two feet cut off, they stagger on their splintered stumps into the next shell-hole; a lance-corporal crawls a mile and a half on his hands dragging his smashed knee after him; another goes to the dressing station and over his clasped hands bulge his intestines; we see men without mouths, without jaws, without faces; we find one man who has held the artery of his arm in his teeth for two hours in order not to bleed to death.

This excerpt displays how war is not glorious. The physical horrors of war are revealed in descriptions of "skulls blown open" and soldiers running on "stumps" where there used to be legs.

At this point in the narrative, Paul has recognized a hollowness to nationalistic calls to war. He knows that love of country cannot offset the terrifying reality of war. We can see this approach to nationalism in the opening of chapter 6. When the platoon passes by a line of coffins that have been newly made, one of the soldiers suggests that the coffins are not for them. However, Paul knows better when he says, "The coffins are really for us. The organisation surpasses itself in that kind of thing." Paul's approach to nationalism is seen in how he recognizes that, at this point in the conflict, the only thing that the nation can do well is prepare its young soldiers for death. Nationalism is seen in the way Paul suggests that the "organization" understands what to do regarding the death of its young. With this, Paul links the death of soldiers to national identity in World War I.