| 变量 | (1) | (2) | (3) |
| R&D1 | R&D2 | R&D3 | |
| 常数项 | −5.106*** | 0.017 | 0.009 |
|
| (−3.617) | (0.401) | (0.457) |
| Model | −0.003 | −0.001 | −0.001 |
|
| (−0.057) | (−0.468) | (−1.633) |
| Controls | 控制 | 控制 | 控制 |
| Ind/Year | 控制 | 控制 | 控制 |
| AdjustedR2 | 0.687 | 0.137 | 0.195 |
| F | 41.37 | 3.926 | 5.456 |
| N | 682 | 682 | 682 |