using Count function

[ambika_se]

hi all
I need a help to use count function. I want to make a query in which i want to search for some keyword
so the query i made was

for $x in doc("file:///C:/Package1.xml")//Package
where $x//node()[contains(.,"Science"))]
return $x

It works fine. But now i want to know how much times the word Science apperared in the XML.
can i use funtion count here
I changed the query to

for $x in doc("file:///C:/Package1.xml")//Package
where $x//Count(node()[contains(.,"Science"))])
return $x

But it does not work . Can u please help me to solve this problem.
Thanks
regards