How many {studied by} are for {atomic nucleus} ?
The atomic nucleus has how many studies?
How many studies are for atomic nucleus?
SELECT ( COUNT ( ?m ) AS ?u ) { resource:atomic_nucleus property:studied_by ?m }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q37147> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P2579> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q37147 wdt:P2579 ?obj }
3