Our search service PATENTSCOPE® (http://www.wipo.int/patentscope/search/en/search.jsf ) can give an indication as to whether a PCT international application has entered the national phase, as well as an indication of the legal status nationally and/or a link to the national office to check this status. This information is only available for PCT applications and when a national office has sent it to WIPO and this is occurs only with 43 countries at the moment, although we are continuing to request and add this information from other countries. To view this information, please go to the "National Phase" tab of the PCT application window.
National reference numbers are not recorded for patent applications that are withdrawn and are instead shown as "null" through the PATENTSCOPE® search service. National phase entry data is updated when such data is received from the relevant national/regional patent offices. For more information on the national phase entry data provided through the PATENTSCOPE® search service, please refer to the following webpage: http://www.wipo.int/pctdb/en/nationalphase.jsp