Evaluation of the clinical efficacy and the safety of minimally invasive radical surgical resection of colorectal cancer.

Interventions: A:small incision open radical operation on colo-rectal carcinoma;B:standard incision open radical operation on colo-rectal carcinoma Primary outcome(s): recovery conditions of intestinal function after operation;operation time;blood loss;hospitalization time;postoperative complication;recovery conditions of anal function after operation Study Design: Non randomized control