function extract(input, keys) {
  output = "";
  while (keys != "") {
    p = pos(keys, "\n");
    if (p > 0) {
      key = left(keys, p - 1);
      keys = mid(keys, p + 1);
    } else {
      key = keys;
      keys = "";
    }

    if (key != "" && pos(input, key) > 0) {
      if (output == "") {
        output = key;
      } else {
        output = output + "\n" + key;
      }
    }
  }
  return output;
}


keys = InputBoxMultiLine("抽出する語句を改行区切りで入力してください。");
if (keys == "") {
  return;
}

for (y = 1; y <= Bottom; y++) {
  [x,y] = extract([x,y], keys);
}