Mount cement counter top
One way to secure the concrete top to your cabinet is to use construction adhesive that is rated for bonding with both wood and concrete. The concrete and wood should be clean and dry before attempting to do the bonding. 

After the adhesive has dried the top will be pretty much permanently bonded to the wood of the cabinet. If you want to have the top be removable you could consider gluing some wood blocks or strips to the concrete that are positioned in such manner that you can add screws through the side of the strip into the cabinet structure. Removing the top would then be a process of taking out these screws and then lifting off the top with its strips/blocks still attached.