for $d in Root('/BookDB/Book') 
where match $d using [/book/title contains "Unix"] 
return $d    

  <book year = '1992'>
    <!--this is another book-->
    <title>
      Advanced Programming in the Unix environment
    </title>
    <author>
      <last>
        Stevens
      </last>
      <first>
        W.
      </first>
    </author>
    <publisher>
      Addison-Wesley
    </publisher>
    <price>
      65.95
    </price>
  </book>
  <book>
    <!--this is another book-->
    <title>
      Advanced Programming in the Unix environment
    </title>
    <price>
      65.95
    </price>
    <review>
      A clear and detailed discussion of UNIX programming.
    </review>
  </book>
  <book>
    <!--this is another book-->
    <title>
      Advanced Programming in the Unix environment
    </title>
    <source>
      www.amazon.com
    </source>
    <price>
      65.95
    </price>
  </book>
  <book>
    <!--this is another book-->
    <title>
      Advanced Programming in the Unix environment
    </title>
    <source>
      www.bn.com
    </source>
    <price>
      65.95
    </price>
  </book>