Metadata for cited GBIF download

First all the download keys were retrieved by using the GBIF literature API (https://www.gbif.org/developer/literature), then the GBIF Registry database was queried to get the metadata information about the downloads.首先通过GBIF文献API（https://www.gbif.org/developer/literature）检索全部下载密钥，随后对GBIF注册数据库进行查询以获取与下载相关的元数据信息。