(下面排版太拧巴。。。使用$代替美元符号)
d=read.table("金融DM文献数量.txt",header=T);
plot(d$id, d$doctor, type='b',xlim=range(1,3.2),ylim=range(1,200),pch=15,col='red',xlab="",ylab="论文数");
lines(d$id, d$master,type='b',pch=16,col='blue');
lines(d$id, d$cnjournal,type='b',pch=17,col='black');
text(d$id, d$$doctor, d$doctor, pos=4, col='red');
text(d$$id, d$$master, d$master, pos=3,col='blue');
text(d$$id, d$$cnjournal, d$cnjournal, pos=4,col='black');
legend("topright",inset=0.05,title="图 例",c("硕士论文","期刊论文","博士论文"),lty=c(1,1,1),pch=c(16,17,15),col=c("blue","black","red"))