problem with the plm package

Dear R help, 
      I use the package plm  the function plm() to analyse a panel data and 
   estimate a fixeffect model.
   I use the code as follow :
    fe <- plm(y~x+z, data, model = "within")
   But my result have no intercept.why?  I consult the paper plm.pdf , but I
can't find any answer.
   Can I estimate a model with intercept?

   Thanks, 
   Helen Chen

View this message in context: http://www.nabble.com/problem-with-the-plm-package-tp22737251p22737251.html
Sent from the R help mailing list archive at Nabble.com.