In this work fundamental properties of the electrical transport of single-walled carbon nanotubes as a function of their length are investigated. For this purpose, we have developed a new technique that allows us to characterize electronic transport properties of single-walled carbon nanotubes by probing them at different spots. This technique uses scanning force microscopy to make mechanical and electrical nanocontacts at any selected spot of a given image. We have applied this technique to molecules with high intrinsic resistance. The results show a nonlinear resistance vs distance behavior as the nanotube is probed along its length. This is an indication of elastic electronic transport in one-dimensional systems.