var s = '1) Number of tube((13 Hi all people * _ +)) Number of tube((HI AKK))',
    r = /Number of tube\(\((.*?)\)\)/g,
    a = [];
while (r.exec(s)) {
    a[a.length] = RegExp.$1;
}
alert(a);

var word = "Number of tube";
var number_of_skobka = 2;
var str = "1) Number of tube((13 Hi all people * _ +)) Number of tube((HI AKK)) Number of Kills ((Privet)) Number of tube((HI HOUSE))";
var reg1 = new RegExp(word+"\\({"+number_of_skobka+"}[^\\)\\(]+(?=\\){"+number_of_skobka+"})","g");
var reg2 = new RegExp(word+"\\({"+number_of_skobka+"}");
alert(reg1.toString());
alert(reg2.toString());
var arr = str.match(reg1).join("").split(reg2);
alert(arr);

str.match(/(?<=Number of tube\({2})[^\(\)]+(?=\){2})/g)