如果Web站点是刚刚建立的，而且在搜索索引中没有其他站点链接到它，那么搜索引擎还没有发现它。

If your Web site is just getting off the ground and no other site in the search index links to yours, the search engines haven't discovered it.

youdao

此目录包含Lucene搜索引擎产生的搜索索引文件，如图10中所示。

This directory contains the search index files produced by the Lucene search engine as shown in Figure 10.

youdao

It's really a technology initiative that's aimed to index the "dark" web or the hidden web, because according to computer scientists, right now the conditional search engines only index about 1% of the information on the Internet.

这是一项,致力于将暗网,或隐藏网页纳入索引的技术创新，根据计算机科学家的统计，条件式的搜索引擎只将,互联网上1%的信息纳入了索引。

斯坦福公开课 - 百度CEO李彦宏演讲：全球最大搜索引擎的发展课程节选