在arcgis api for javascript 3.43中，我有一个地图服务和四个要素服务，我把它们作为不同的图层加载在地图上，现在我要怎么控制这些图层的显示呢？

您可以使用ArcGIS API for JavaScript 3.43中的`setVisibleLayers()`方法来控制要素图层的显示。

以下是一个示例代码，用于控制地图服务和四个要素服务的显示：

//加载地图服务
var mapServiceLayer = new esri.layers.ArcGISDynamicMapServiceLayer("http://yourserver/arcgis/rest/services/YourMapService/MapServer");
map.addLayer(mapServiceLayer);

//加载四个要素服务
var featureLayer1 = new esri.layers.FeatureLayer("http://yourserver/arcgis/rest/services/YourFeatureService1/FeatureServer/0");
var featureLayer2 = new esri.layers.FeatureLayer("http://yourserver/arcgis/rest/services/YourFeatureService2/FeatureServer/0");
var featureLayer3 = new esri.layers.FeatureLayer("http://yourserver/arcgis/rest/services/YourFeatureService3/FeatureServer/0");
var featureLayer4 = new esri.layers.FeatureLayer("http://yourserver/arcgis/rest/services/YourFeatureService4/FeatureServer/0");
map.addLayers([featureLayer1, featureLayer2, featureLayer3, featureLayer4]);

//设置默认显示的图层
var visibleLayers = [0, 1, 2, 3, 4];
mapServiceLayer.setVisibleLayers(visibleLayers);
featureLayer1.setVisibility(false);
featureLayer2.setVisibility(false);
featureLayer3.setVisibility(false);
featureLayer4.setVisibility(false);

//添加控件用于控制图层显示
var layerList = new esri.dijit.LayerList({
  map: map,
  layers: [mapServiceLayer, featureLayer1, featureLayer2, featureLayer3, featureLayer4]
}, "layerListDiv");
layerList.startup();

//定义事件处理程序，当用户选择要显示的图层时，将其设置为可见状态
dojo.connect(layerList, "onLayerClick", function(item) {
  var visibleLayers = [];
  dojo.forEach(layerList.getLayerVisibleItems(), function(layer) {
    visibleLayers.push(layer.id);
  });
  mapServiceLayer.setVisibleLayers(visibleLayers);
});

在上面的示例中，首先加载地图服务和四个要素服务，并将它们作为不同的图层添加到地图中。然后，通过`setVisibleLayers()`方法设置默认显示的图层，并将所有要素图层的可见性设置为false。接下来，添加一个控件用于控制图层的显示，并定义事件处理程序，当用户选择要显示的图层时，将其设置为可见状态。