Humans article human 1,693 priority journal 1,159 controlled study 1,109 Animals 829 nonhuman 754 Female 678 Male 631 human cell 631 female 618 male 564 adult 487 unclassified drug 449 Adult 440 protein expression 334 Mice 316 animal cell 315 Middle Aged 306 metabolism 279 mouse 267 Argentina 256 animal 249 physiology 231 Aged 203 clinical article 198 signal transduction 195 Cell Line, Tumor 190 animal experiment 188 cell proliferation 187