Human Evolution Extinct?

According to the theory of evolution, mutations occur within a species.  When these mutations are harmful, the organism is less likely to reproduce, and the gene is removed from the gene pool.  However, when the mutation is beneficial, the organism is more likely to pass on the gene and have it become a normal trait.  This is exactly how every species arrived to their current disposition.  It could also be noted that if there are no pressures or forces against these mutations, that the weaker and harmful mutations would subsequently survive and reproduce.  In humans, there are no real pressures that would wipe out these mutations in modern times.  Medical science has improved so much that diseases that would have killed people in their childhood can now live happy and fulfilling lives.  Would this ultimately make humans weaker, or will it have some other unforeseen circumstance?  Are some of these mutations actually beneficial?  Does human evolution still exist?