One of the most important reasons why you can't upload files when checking duplicate papers is that browsers don't support it, such as 360 browsers, but you can upload them again by changing browsers. It is also possible that your file format is wrong or the file size is limited.

Whip. Com, formerly known as "VIP Information Network", is a website founded by Chongqing VIP Information Co., Ltd., the founder of China periodical database construction. Since 1989, it has been committed to the scientific and rigorous research, analysis, collection, processing and other in-depth development and promotion of massive newspaper data.

Whip. Com was founded in 2000. After 16 years of commercial construction, it has become a world-renowned Chinese information service website, the largest comprehensive literature service network in China, a heavyweight partner of GOOGLE search, and the largest Chinese content cooperation website of GoogleScholar. China Sci-tech Periodical Database is the largest digital periodical database in China. Since its launch, the database has been widely concerned and praised by the domestic library and information circles. It is one of the core resources of online digital library construction in China, and is widely used by universities, public libraries and scientific research institutions in China. It is an important part of the literature guarantee system of university libraries, and it is also an essential database for scientific researchers to carry out sci-tech novelty retrieval and novelty retrieval. At present, there are more than 5,000 enterprises and institutions including Hong Kong, Macao and Taiwan, with more than 3 million registered users, providing readers with more than 800 million reading services. It has achieved the goal of serving the society with information technology and promoting China's scientific and technological innovation.