def get_null_keywords_es(es, size):
    """
    Get from ElasticSearch the news entries which don't contain keywords.

    :param es: ElasticSearch connection
    :param size: limit of news which are retrieved
    :return: list of news without keywords
    """
    result = es.search(index='sitemaps', q='-news\\:keywords:*',
        _source_includes='news:keywords', size=size)
    return result['hits']['hits']
