controlled study priority journal article 1,368 nonhuman 1,308 Animals 873 animal experiment 594 animal cell 562 male 548 female 535 human 525 Humans 461 Female 448 animal tissue 444 Male 437 unclassified drug 423 mouse 418 Mice 359 protein expression 349 Article 309 rat 291 human cell 290 animal model 288 metabolism 280 animal 257 Rats 234 enzyme activity 231 adult 209 signal transduction 185 in vitro study 164 physiology 147