Approval.

backend/es/basis.json

@@ -152,6 +152,10 @@
         "not": "not",
         "search_term": "Search term",
         "and": "and",
-        "refine_search": "Refine search"
+        "refine_search": "Refine search",
+        "exact": "Exact",
+        "greater_than": "Greater than",
+        "lower_than": "Lower than",
+        "empty": "Empty"
     }
 }