变量

(1)

(2)

(3)

R&D1

R&D2

R&D3

常数项

0.258

0.115^***

0.075^***

(0.219)

(3.988)

(5.143)

Model

−0.281^***

−0.006^***

−0.004^***

(−5.381)

(−4.876)

(−5.592)

Size

0.722^***

−0.005^***

−0.003^***

(25.170)

(−6.496)

(−7.327)

Lev

−0.109

−0.028^***

0.000

(−0.694)

(−7.372)

(0.012)

Roa

1.553^***

−0.014

0.024^***

(4.061)

(−1.486)

(5.166)

Growth

0.132

−0.000

0.000

(1.605)

(−0.241)

(0.298)

Cash

1.286^***

−0.001

0.021^***

(3.423)

(−0.144)

(4.654)

Firmage

0.117^*

0.001

0.002^***

(1.920)

(1.001)

(2.615)

Fn

−0.006

−0.001^*

−0.000

(−0.395)

(−1.832)

(−0.398)

Fd

−0.322^**

−0.006^*

−0.003^*

(−2.383)

(−1.861)

(−1.802)

Indep

−0.062

0.014

−0.005

(−0.144)

(1.375)

(−0.981)

Sex_er

0.213^***

0.005^***

0.003^***

(2.965)

(2.606)

(3.280)

Age_er

0.094

0.025^***

0.008^***

(0.390)

(4.178)

(2.812)

Degree_er

0.040

−0.000

0.001

(1.322)

(−0.117)

(1.360)

PC_er

0.093^***

0.001^**

0.001

(3.362)

(2.040)

(1.639)

Sex_yi

−0.028

0.006^**

−0.001

(−0.268)

(2.336)

(−0.735)

Age_yi

−0.274

−0.026^***

−0.013^***

(−0.710)

(−2.719)

(−2.741)

Site

0.323^***

0.001

0.003^***

(8.690)

(1.615)

(6.063)

Ind/Year

控制

控制

控制

AdjustedR²

0.551

0.260

0.287

F

36.48

11.17

12.67

N

1101

1101

1101