Efficacy of Root and Pylorus formula combined with Sijunzi Tang in treating drug-resistant Helicobacter pylori-infected chronic atrophic gastritis with splenic deficiency and damp-heat syndrome and its effect on COX-2 and Ki-67 levels (根幽方合四君子汤治疗耐药幽门螺杆菌感染慢性萎缩性胃炎脾虚湿热证疗效及对COX-2, Ki-67水平的影响).