Lucene search problem

i making a query in node-browser of alfresco 4.2.f version, my search is for a specific property of my custom model, the result of this query is not satisfactory, the query brings me all nodes of repository with my specific type "TYPE:"myprefix:document", the nodes don't have a custom property "myprefix:myproperty" and similarly get the node in query result.

this is my query:

TYPE:"myprefix:document" AND @myprefix\:myproperty:"IT"

and this is other one

TYPE:"myprefix:document" AND @myprefix\:myproperty:"OR"

Any idea?