animal model priority journal nonhuman 180 rat 176 animal experiment 166 controlled study 158 article 144 Rats 138 Animals 130 animal tissue 94 female 84 animal cell 78 male 76 Female 72 Male 64 Rats, Wistar 52 protein expression 52 Rats, Sprague-Dawley 50 unclassified drug 28 Animalia 24 Article 24 Disease Models, Animal 24 Mice 24 animal 24 enzyme activity 24 immunohistochemistry 24 mouse 24 Western blotting 22 Animals, Newborn 20 Humans 20