百度关键词搜索量
http://www2.baidu.com/inquire/rsquery.php

google关键词工具
https://adwords.google.com/select/KeywordToolExternal

YAHOO
http://customer.p4p.cn.yahoo.com/keyword/kwwhois.htm

SOHU关键词排序
http://db.sohu.com/regurl/pv_price/query_consumer.asp

网易
http://adpsearch.163.com/find_price.php

OVERTRUE
http://inventory.overture.com/d/searchinventory/suggestion/

GOOGLE热门关键字查询:
http://www.google.com/press/zeitgeist.html

关键词变化趋势:
http://www.google.com/trends

GOOGLE特殊功能(包括翻译,计算器,汇率计算,股票查询,邮编查询...)


百度热门关键字查询:
http://top.baidu.com/