变量 | (1) | (2) | (3) | (4) |
patent | TQ | RDS | TQ | |
Did | 0.267*** | 0.0459** | 0.156*** | 0.0431* |
| (0.0439) | (0.0221) | (0.0257) | (0.0221) |
patent |
| −0.0209*** |
|
|
|
| (0.00461) |
|
|
RDS |
|
|
| −0.0173** |
|
|
|
| (0.00726) |
常数 | −7.504*** | 3.164*** | 0.393 | 3.327*** |
| (0.402) | (0.189) | (0.302) | (0.190) |
控制变量 | 控制 | 控制 | 控制 | 控制 |
固定效应 | 是 | 是 | 是 | 是 |
| 0.236 | 0.685 | 0.545 | 0.685 |
样本数 | 8,850 | 8,850 | 8,850 | 8,850 |