RL | Description | Examples |
1 | Clinical observation | Am J Gastroenterol; BMJ;Endoscopy; Dis Colon Rectum; Gastrointest Endosc |
2 | Clinical mix | Cancer;Dig Dis Sci;Gastroenterology;Gut;Hepatology;Lancet; N Engl J Med |
3 | Clinical investigation | Cancer Res;Gastroenterol Clin North Am; Infect Immun; J Clin Invest |
4 | Basic research | Am J Physiol;J Biol Chem; J Physiol; Nature;Proc Nat Acad Sci USA |