php调用百度翻译api后，调用成功后为什么结果为空？

Question

       $ch = curl_init();
             //$keyword='hello';
    $url = 'http://apis.baidu.com/apistore/tranlateservice/dictionary?query=hello&from=en&to=zh';
    $header = array(
        'apikey: 这里是我的apikey,我没有写',
    );
    // 添加apikey到header
    curl_setopt($ch, CURLOPT_HTTPHEADER  , $header);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    // 执行HTTP请求
    curl_setopt($ch , CURLOPT_URL , $url);
    $res = curl_exec($ch);
    curl_close($ch);
    var_dump(json_decode($res));

Answer 1

<?php
    $ch = curl_init();
    $url = 'http://apis.baidu.com/baidu_openkg/zici_kg/zici_kg';
    $header = array(
        'Content-Type:application/x-www-form-urlencoded',
        'apikey: a32f233654d52b869c0e96dd6b3e2db7',
    );
    $data = '{"query": "喜欢近义词", "resource": "zici"}';
    // 添加apikey到header
    curl_setopt($ch, CURLOPT_HTTPHEADER  , $header);
    // 添加参数
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    // 执行HTTP请求
    curl_setopt($ch , CURLOPT_URL , $url);
    $res = curl_exec($ch);

    $var = json_decode($res, true);
    print_r($var);
?>