Reasons for not finding relevant patents may include:

1. This patent does not exist.
2. The invention is currently not disclosed/announced and is in a confidential patent application status.This time generally ranges from a few months to over a dozen months from the date of application; please check back later.
3. Search criteria are incorrect.Please verify if incorrect field restrictions were applied to the search criteria.
4. The search keyword range is too narrow.Please try using other keywords or synonyms, or use broader keywords.
5. Abnormal search request.

Please pay special attention:

• The system will split keywords by default. If you do not wish to split, please use "" to restrict the phrases for more precise results.
• Patent numbers can be entered arbitrarily, with or without country codes or check digits.
• Partial classification numbers can be entered.
• Dates can be searched by year, year and month, or year, month, and day.

For more complex logical queries, please refer to《帮助文档》, 数据库使用教程.pdf