use articles
db.stores.insert( [ {_id : 1, arr : ['abc xyz', 'def']}, {_id : 2, arr : ['jadskf', 'ljh abc']}])
db.stores.createIndex({"arr" : "text"})

> db.stores.find({$text : {$search : "abc"}})
{ "_id" : 1, "arr" : [ "abc xyz", "def" ] }
{ "_id" : 2, "arr" : [ "jadskf", "ljh abc" ] }