| 2001-2006年 | | 2007-2013年 | | 全国 | 东部 | 中部 | 西部 | 东北 | 全国 | 东部 | 中部 | 西部 | 东北 | xc, i, t1 | 0.549*** | 0.674*** | 0.581*** | 0.465*** | 0.505*** | | 0.566*** | 0.619*** | 0.560*** | 0.478*** | 0.571*** | | (0.021) | (0.019) | (0.016) | (0.021) | (0.037) | | (0.017) | (0.019) | (0.016) | (0.022) | (0.058) | density×(1-xc, i, t1) | 1.728*** | 3.191*** | 3.930*** | 0.438* | 2.882*** | | 2.410*** | 2.457*** | 3.801*** | 1.939*** | 1.446** | | (0.468) | (0.179) | (0.347) | (0.228) | (0.334) | | (0.163) | (0.123) | (0.242) | (0.398) | (0.593) | density×xc, i, t1 | 1.594*** | 1.880*** | 2.994*** | 1.315*** | 2.562*** | | 1.721*** | 1.601*** | 2.694*** | 1.716*** | 0.721 | | (0.234) | (0.178) | (0.286) | (0.221) | (0.458) | | (0.217) | (0.128) | (0.225) | (0.370) | (0.991) | City Fe | Yes | Yes | Yes | Yes | Yes | | Yes | Yes | Yes | Yes | Yes | Product Fe | Yes | Yes | Yes | Yes | Yes | | Yes | Yes | Yes | Yes | Yes | _cons | -0.032** | -0.143*** | -0.056*** | -0.000 | -0.070*** | | -0.061*** | -0.126*** | -0.069*** | -0.020* | -0.046 | | (0.016) | (0.016) | (0.009) | (0.008) | (0.020) | | (0.009) | (0.016) | (0.013) | (0.012) | (0.034) | N | 375024 | 100968 | 93756 | 137028 | 43272 | | 375024 | 100968 | 93756 | 137028 | 43272 | R2 | 0.580 | 0.587 | 0.430 | 0.418 | 0.518 | | 0.566 | 0.577 | 0.432 | 0.426 | 0.490 |
|