我试图使用以下服务：
file_get_contents(http://webservices.amazon.es/onca/xml?AWSAccessKeyId=[MYACCESSKEY]&AssociateTag=[MYTAG]&BrowseNode=&ItemPage=1&Keywords=Book&Operation=ItemSearch&ResponseGroup=BrowseNodes%2CEditorialReview%2CImages%2CItemAttributes%2CItemIds%2CSalesRank%2CAlternateVersions&SearchIndex=Books&Service=AWSECommerceService&Sort=salesrank&Timestamp=2017-08-01T17%3A02%3A58Z&Version=2015-10-01&Signature=XI23CQHWPRTChJ%2F6Mheajw4OBfAm%2BvhdoGlHK0ap1II%3D);
它让我＆＃34;缺少参数操作。＆＃34;但它是Operation = ItemSearch