欧洲专利局检索遇到的问题

用欧洲专利局“quick search”检索，显示“Approximately 91 results found in the Worldwide database for:。。。。。”，浏览完第一页后，点击next进入第二页，发现变成了“Approximately 88 results found in the Worldwide database for“
第三页变成了“Approximately 67 results found in the Worldwide database for“
第四页变成了“Approximately 52 results found in the Worldwide database for“
而且总共只显示了52个结果，
请问这是问什么？
就因为”Approximately“？
谢谢

高人呢？

可以参照EPO检索结果页面的quick help---
Why is the number of results sometimes approximate?
It is not always possible to know immediately following a search exactly how many results will be displayed. In such cases, an approximate number is given, which is generally slightly higher than the actual number of results. This approximate number might change as you go through the results pages, as we only display one patent document per family (ie duplicates are eliminated).

thank you