Full wave bridge rectifier circuit in multisim
Your voltage source V1 has a peak voltage of just 1V, your lecturer had a voltage source of 10V. In a bridge rectifier circuit the current has to flow through 2 diodes which will have a voltage drop of about 0.7V each, ie 1.4V. So I would not expect to get any voltage from your circuit at all.

Also, you have put the ground reference at the wrong point. I would put it at the R1 / R3 junction.