Index: django/contrib/admin/views/main.py
===================================================================
--- django/contrib/admin/views/main.py	(revision 6289)
+++ django/contrib/admin/views/main.py	(working copy)
@@ -61,7 +61,7 @@
     res = list(s)
     for i in range(len(res)):
         c = res[i]
-        if c in ':/_':
+        if c in ':/_#?@=&':
             res[i] = '_%02X' % ord(c)
     return ''.join(res)