Dear jrserrano,
I think it is correct what your are trying to do but the syntax is not completely correct because it is missing a $ character. The right syntax to use is: WHERE clinica LIKE '%$P{clinicaname}%'. Remember also to use the type Raw or Generic for the parameter clinicaname.
I hope you find this information useful, but if you were looking for something different, please answer again!
Thank you ifassi, now it works!
Really my problem was the type i had chosen "string" and it didn't work.
Regards.