Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 197
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 197
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 271
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3165
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 597
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 511
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 317
Function: require_once
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With the increasing complexity of technology, cross-regional joint patent applications and patent transfers have become a prominent component of knowledge activities, attracting substantial attention of academic researchers. To examine the state and distribution characteristics of inter-city knowledge flows, this study utilizes patent data from the China National Intellectual Property Administration database and conducts in-depth data exploration to construct two urban knowledge networks (UKN). Specifically, over 1.23 million value co-creation patents are extracted to develop the urban value co-creation knowledge network (UKN-C), while more than 1.42 million technology transfer patents are refined to establish the urban technology transfer knowledge network (UKN-T). Both UKNs start with cities as nodes and knowledge connections between cities as edges. The edges of UKN-C are weighted by the volume of value co-creation patents, whereas the edges of UKN-T are weighted by the volume of technology transfer patents. To facilitate further research, the geographically explicit and spatial-temporal knowledge flow networks have been released in a simple and accessible format.
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Source |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC12259858 | PMC |
http://dx.doi.org/10.1038/s41597-025-05589-2 | DOI Listing |