Objective: To explore the relationship between social support and internet addiction in undergraduates. Method: 382 undergraduates were divided into three groups according to their social support score and perceived social support score at end of the first term in their freshmen year. They were followed for 4.5 years to collect the incidence of internet addiction. Results: The group with less social support or less perceived social support had higher incidence rate (15.7%, 7.9% and 2.4% with social support score 0～60, 61～73 and higher than 73 respectively, ?2=9.49,P=0.009). There was obvious dose-effect relationship between social support and incidence of internet addiction. Conclusion: Less social support is a risk factor of internet addiction.

0.05). The pulmonary carcinoma incidence rate of the rats treated at the dosages of (6.88?0.31) mg/m3, (15.06?0.35) mg/m3 and (35.33?1.69) mg/m3 were 6.56%?8.96% and 12.70% respectively. Immunohistochemical staining showed that COF could induce abnormal expression of p53 and FHIT protein in lung tissue. Only in experimental group the positive expression of mutant p53 protein located in bronchi epithelial cell nucleus were found. The positive expression rate of p53 protein in lung tissue section of tumor cases was significantly higher than that of control group(P