Humans animal experiment unclassified drug nonhuman 92 controlled study 90 Animals 88 human 82 mouse 74 animal model 66 Mice 64 priority journal 57 animal 56 article 56 animal cell 51 human cell 46 metabolism 46 protein expression 45 Female 43 female 43 in vivo study 35 Article 34 Male 34 in vitro study 31 animal tissue 26 drug effects 26 pathology 25 male 24 tumor growth 23 cell proliferation 21 chemistry 21