The Safety and Efficacy of PD-1 Monoantrapical Chemotherapy in the Treatment of Local Advanced Stomach Cancer

"Drug:~Camrelizumab 200mg,d1，Repeat every 21 days for 3 courses； Oxaliplatin 130mg/m² ,d1;S-1 40-60mg,Bid, d1-14; S-1: bsa\<1.25m2,40mg/time，twice a day；bsa1.25\~1.5m2，50mg/time，twice a day；bsa≥1.5m2,60mg/次，twice a day，d1-d14；~Procedure: Gastric cancer resection Distal gastrectomy combined with D2 lymph node dissection"