sepration of files on the basis of there name

I have a folder containing lots of files like 3 lac plus files. I have to separate them according to their names in three different folders. e.g. a few names are: 7msf_stem_0_mcannotate.pdb 7msf_loop_3_mcannotate.pdb 6tna_strand_10_mcannotate.pdb 7msf_strand_4_mcannotate.pdb

I have to keep all the files containing "stem" in their name in one folder called stem, those containing "loop" in their names in another folder called loops, while those containing "strand" in their name called strands. Is their a shell script to do that?