变量及数据样例:
展示方便,格式实际为分析用得面板格式。
code |
company name |
list day |
year |
R&D expense |
R&D expense/total sales |
intangible assets/total assets |
roa |
roe |
q |
ros |
eps |
sales growth |
profit margin |
firm size |
industry |
leverage |
firm age |
marketcap |
total assets |
total sales |
intangible assets |