include("../sqlConnection/connection.php");
$data = json_decode(file_get_contents("php://input"));
$search = $data->fRegistro;
$sql = "SELECT * FROM listafinanceira LIMIT $search";
$stmt = $PDO->prepare( $sql );
$stmt->bindParam(1, $search , PDO::PARAM_INT);
$stmt->execute();

$result = $stmt->fetchAll(PDO::FETCH_ASSOC);

echo json_encode($result);

$scope.displayData = function()
    {
        $http.get("../sqlFunctions/selectForm.php",
            {'fRegistro':$scope.fRegistro}

            ).then(function(response){
            $scope.entradas = response.data;
        });
    }

$scope.displayData = function()
    {
        $http.get("../sqlFunctions/selectForm.php", {
            params: {
                'registro': $scope.fRegistro
            }
            }).then(function(response){
            $scope.entradas = response.data;
        });
    }

<select name="tipo" ng-model="fRegistro" ng-init="fRegistro='10'" ng-class="['uk-select','uk-form-width-small','uk-form-small']">
                    <option value="10">10</option>
                    <option>25</option>
                    <option>50</option>
                    <option>100</option>
</select>