博客阅读器只能获取第一页的内容，历史内容就无法获取了，利用Google Api也可以获取历史记录，因为google已经将历史记录保存在他自己的数据库中了。
具体参数可以参考
http://code.google.com/p/pyrfeed/wiki/GoogleReaderAPI
url例子：
http://www.google.com/reader/atom/feed/http:/www.cnblogs.com/rock_chen/rss?n=10
参数：（摘自Api）
|
GET parameter name |
python Google Reader API name |
parameter value |
|
n |
count |
Number of items returns in a set of items (default 20) |
|
client |
client |
The default client name (see client in glossary) |
|
r |
order |
By default, items starts now, and go back time. You can change that by specifying this key to the value o (default value is d) |
|
ot |
start_time |
The time (unix time, number of seconds from January 1st, 1970 00:00 UTC) from which to start to get items. Only works for order r=o mode. If the time is older than one month ago, one month ago will be used instead. |
|
ck |
timestamp |
current time stamp, probably used as a quick hack to be sure that cache won't be triggered. |
|
xt |
exclude_target |
another set of items suffix, to be excluded from the query. For exemple, you can query all items from a feed that are not flagged as read. This value start with feed/ or user/, not with !http:// or www |
|
c |
continuation |
a string used for continuation process. Each feed return not all items, but only a certain number of items. You'll find in the atom feed (under the name gr:continuation) a string called continuation. Just add that string as argument for this parameter, and you'll retrieve next items. |