# 在线检索限制性

有些本地搜索的选项并不适用于在线检索数据库，例如一些数据库禁止搜索一年内的文献，此时就不能检索 2015 年的文献，但是允许检索作者是 Howsci 和发表年代 2015 年的文献

如果检索式不适用于当前在线数据库，会出现错误信息，详见[连接错误](https://app.gitbook.com/s/-LrgCHEEK5wsSALfCziF/online-databases/Appendices/TroubleShooting_Connctns.htm)。时刻记住这些限制条件不是 EndNote，而是数据库公司限制的


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://kb.howsci.com/online-databases/online-database-searching/online-database-search-limitations.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.