diff --git a/tabellio/searchform/simple.py b/tabellio/searchform/simple.py
index 44cc561..65e3ce1 100644
--- a/tabellio/searchform/simple.py
+++ b/tabellio/searchform/simple.py
@@ -120,11 +120,18 @@ class SimpleSearchView(BrowserView):
         if not self.request.form.get('SearchableText'):
             return []
         sorton = self.request.form.get('docs-sort', 'session')
+        search_query = self.request.form.get('SearchableText')
+        try:
+            int(search_query)
+        except ValueError:
+            kwargs = {'SearchableText': search_query}
+        else:
+            kwargs = {'nodoc': search_query}
         c = catalog(
                 portal_type=['tabellio.documents.dossier',
                              'tabellio.documents.document',
                              'tabellio.documents.question'],
-                SearchableText=self.request.form.get('SearchableText'))
+                **kwargs)
         if sorton == 'session':
             cmpf = cmpfunctions.Cmp().cmp_session
         elif sorton == 'type':