[Question]: knowledge question

### Self Checks

- [x] I have searched for existing issues [search for existing issues](https://github.com/infiniflow/ragflow/issues), including closed ones.
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- [x] Non-english title submitions will be closed directly ( 非英文标题的提交将会被直接关闭 ) ([Language Policy](https://github.com/infiniflow/ragflow/issues/5910)).
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### Describe your problem

请问知识库的分块给他设置问题和关键词，他们是存入哪个位置的，检索的时候怎么检索回来计算相似度的？

No files, tests, or entry points are named; this is a question rather than a defined code change. Start by locating the knowledge-base chunking and retrieval documentation or implementation, then document where questions and keywords are stored and how similarity retrieval returns them.

Written by the indexing model from the issue text.