GET /_search
{
    "query": {
        "bool": {
            "should": [
                {
                    "constant_score": {
                        "boost": 3,
                        "query": { "match": { "fulltext": "cylinder" }}
                    }
                },
                {
                    "constant_score": {
                        "boost": 2,
                        "query": { "match": { "fulltext": "crankshaft" }}
                    }
                },
                {
                    "constant_score": {
                        "query": { "match": { "fulltext": "engine" }}
                    }
                }
            ]
        }
    }
}