https://diff.wikimedia.org/2021/05/11/adding-dois-to-chinese-scientific-articles-on-wikidata/
“In recent years, China has become the world’s largest producer of scientific articles. However, bibliographic data of Chinese scientific articles are still very limited on Wikidata, because most commonly used bibliographic databases on Wikidata, such as Crossref, do not include articles published in most Chinese academic journals. There have been some efforts to import Chinese articles from China National Knowledge Infrastructure (CNKI), the most comprehensive database for Chinese articles. But for most articles on CNKI, there is no DOI information (the exception is when the resolved pages are hosted by CNKI itself). DOI is a key component for developing a database of open citations and linked bibliographic data, so it would be very beneficial to collect such information and add them to Wikidata. There is no available database containing comprehensive DOIs for Chinese articles, and many DOIs can only be found on journals’ official websites. A WikiCite e-scholarship was granted to develop a tool to collect those data scattered across different journal websites. During the development, more than 20,000 DOIs have already been added to Wikidata.”