We investigate here the nonlinear elliptic equations -Delta u = vertical bar x vertical bar(alpha)e(u) and -Delta u = vertical bar x vertical bar(alpha)vertical bar u vertical bar(p-1)u with alpha > -2, p > 1 and N >= 2. In particular, we prove some Liouville type theorems for weak solutions with finite Morse index in the low dimensional Euclidean spaces or half spaces. (C) 2011 Elsevier Inc. All rights reserved.