  The dipolar collision between ultracold polar molecules is an important topic
both by its own right from the fundamental point of view and for the successful
exploration of many-body physics with strong and long-range dipolar
interactions. Here, we report the investigation of collisions between ultracold
ground-state sodium-rubidium molecules in electric fields with induced electric
dipole moments as large as 0.7$\;$D. We observe a step-wise enhancement of
losses due to the coupling between different partial waves induced by the
increasingly stronger anisotropic dipolar interactions. Varying the temperature
of our sample, we find good agreement with theoretical loss rates assuming
complex formation as the main loss process. Our results shed new light on the
understanding of complex molecular collisions in the presence of strong dipolar
interactions and also demonstrate the versatility of modifying molecular
interactions with electric fields.
