  We obtain a sequence of solutions converging to zero for the Kirchhoff
equation $$-\left( 1+\int_{\Omega}\left\vert \nabla u\right\vert^2\right)
\Delta u+V(x)u=f(u)\text{,\qquad}u\in H_{0}^{1}(\Omega)$$ via truncating
technique and a variant of Clark's theorem due to Liu--Wang, where $\Omega$ is
a bounded smooth domain $\Omega\subset\mathbb{R}^N$. Similar result for
Schr\"{o}dinger-Poisson system on a bounded smooth domain
$\Omega\subset\mathbb{R}^3$ is also presented.
