article nonhuman 2,648 priority journal 2,616 controlled study 2,264 Animals 1,888 animal cell 1,116 unclassified drug 1,086 human 1,064 Humans 1,056 protein expression 1,022 metabolism 872 animal experiment 782 Mice 778 mouse 766 human cell 684 female 678 male 672 Female 644 animal tissue 632 Male 594 enzyme activity 556 signal transduction 550 genetics 510 animal 502 rat 500 Rats 494 Molecular Sequence Data 464 protein function 456 messenger RNA 386 animal model 380