模型1

模型2

模型3

模型4

RDI

40464317.8*

0.0391***

291232356.1***

0.0796***

(1.82)

(3.70)

(4.16)

(3.35)

Firm size

987741222.7***

−0.210***

1.43664e+09***

−0.225***

(19.61)

(−8.36)

(17.88)

(−8.25)

Debt ratio

−2.37307e+09***

−0.890***

−3.96644e+09***

−0.876***

(−6.53)

(−4.66)

(−7.03)

(−4.58)

TAT

273743321.3

0.080

526061667.1**

0.0822

(1.55)

(0.90)

(2.00)

(0.92)

Cash

243123773.4

0.663**

1.41E+09

0.633*

(0.38)

(2.02)

(1.46)

(1.93)

TAG

642131830.3*

0.111

−28187930.9

0.103

(1.84)

(0.67)

(−0.06)

(0.62)

Duality

211233755.6

−0.157*

579603100.8**

−0.146

(1.24)

(−1.66)

(2.07)

(−1.54)

OBH

−179065742.9*

0.0146

22812222.6

0.0753

(−1.83)

(0.28)

(0.10)

(1.02)

OC

5.91870e+09***

0.757**

(5.23)

(1.97)

RDIoc

−875810620.9***

−0.119*

(−4.75)

(−1.90)

cons

−2.19247e+10***

7.578***

−3.52561e+10***

7.479***

(−18.53)

(12.63)

(−19.75)

(12.37)

N

1030

1030

1030

1030

年度虚拟变量

控制

控制

控制

控制

行业虚拟变量

控制

控制

控制

控制

Adj-R-Squared

0.4255

0.514

0.4791

0.4899