In 2005, OA in the biomedical field was achieved under an umbrella of existing scholarly communication systems. Typically, OA articles were published as part of subscription journals published by scholarly societies. OA journals published by BioMed Central contributed to a small portion of all OA articles.

IntroductionThis study clarifies the trends observed in open access (OA) in the biomedical field between 2006 and 2010, and explores the possible explanations for the differences in OA rates revealed in recent surveys.MethodsThe study consists of a main survey and two supplementary surveys. In the main survey, a manual Google search was performed to investigate whether full-text versions of articles from PubMed were freely available. Target samples were articles published in 2005, 2007, and 2009; the searches were performed a year after publication in 2006, 2008, and 2010, respectively. Using the search results, we classified the OA provision methods into seven categories. The supplementary surveys calculated the OA rate using two search functions on PubMed: “LinkOut” and “Limits.”ResultsThe main survey concluded that the OA rate increased significantly between 2006 and 2010: the OA rate in 2010 (50.2%) was twice that in 2006 (26.3%). Furthermore, majority of OA articles were available from OA journal (OAJ) websites, indicating that OAJs have consistently been a significant contributor to OA throughout the period. OA availability through the PubMed Central (PMC) repository also increased significantly. OA rates obtained from two supplementary surveys were lower than those found in the main survey. “LinkOut” could find only 40% of OA articles in the main survey.DiscussionOA articles in the biomedical field have more than a 50% share. OA has been achieved through OAJs. The reason why the OA rates in our surveys are different from those in recent surveys seems to be the difference in sampling methods and verification procedures.

The purpose of the article is to show the current status of Open Access (OA) in biomedical field, and compare some countries such as the U.S., the U.K. and

Open access (OA) is transforming scholarly communication. Various modes of OA implementation have emerged, which reflect the complexity surrounding OA development. This study aimed to examine this development from the perspective of how OA is implemented. The sample comprised 2,368 randomly selected articles published in 2013 and 2,999 published in 2018 indexed in the Web of Science. We also conducted searches in Google and Google Scholar in 2015 for articles published in 2013 and in 2020 for articles published in 2018. Selected articles were categorized as either an “OA article,” “electronic subscription journal article,” or “not available online.” OA articles were classified into 10 implementation modes: Gold, Hybrid, Delayed, Bronze, Subject Repositories, Institutional Repositories, Personal/Institutional Websites, Academic Social Networks (ASNs), Others, and Web Aggregator. Overall, 56.5% of all sampled articles in 2013 were available for free on at least one website in 2015, while 61.7% of all sampled articles in 2018 were freely available on at least one website in 2020. Concerning implementation mode, ASNs had the highest frequency (44.4% in 2015 and 56.0% in 2020), followed by Subject Repositories (35.0% in 2015 and 39.6% in 2020) and Gold (24.1% in 2015 and 37.4% in 2020). To obtain an overview of OA implementation, we conducted principal component analysis with OA implementation mode as the variable for both 2015 and 2020. The first principal component was the axis indicating the number of overlapping OA implementations for each article in 2015 and 2020, while the second principal component was the axis orthogonal to the first, which was difficult to interpret. We identified three groups of OA implementation in each plot of the principal component scores for articles in 2015 and 2020; however, the OA implementation of each group differed in 2015 and 2020. This diversity reflects the respective positions of various stakeholders regarding OA.

This study was designed to document the state of open access (OA) in the biomedical field in 2009. PubMed was used to collect bibliographic data on target articles published in 2009. Google and PubMed were then used to establish the availability of free full‐text online versions for these articles. Articles were analyzed according to the type of OA to provide insight into the characteristics of OA. The main finding was that almost half of the articles were accessible as OA articles, indicating that OA has progressed rapidly since our previous surveys reported for 2005 and 2007. More than half of the OA articles in the biomedical field are provided by Open Access Journals, the so‐called ‘Gold Road’. PubMed Central is used for journal publishers to archive their contents freely. The percentage of OA articles accessible via institutional repositories (IR) and authors' websites, or the ‘Green Road’, has consistently remained low.