全文获取类型
收费全文 | 16999篇 |
免费 | 166篇 |
国内免费 | 31篇 |
专业分类
教育 | 11313篇 |
科学研究 | 2449篇 |
各国文化 | 129篇 |
体育 | 1538篇 |
综合类 | 8篇 |
文化理论 | 158篇 |
信息传播 | 1601篇 |
出版年
2021年 | 172篇 |
2020年 | 233篇 |
2019年 | 381篇 |
2018年 | 495篇 |
2017年 | 469篇 |
2016年 | 418篇 |
2015年 | 277篇 |
2014年 | 361篇 |
2013年 | 3017篇 |
2012年 | 423篇 |
2011年 | 395篇 |
2010年 | 390篇 |
2009年 | 354篇 |
2008年 | 365篇 |
2007年 | 370篇 |
2006年 | 310篇 |
2005年 | 288篇 |
2004年 | 266篇 |
2003年 | 237篇 |
2002年 | 253篇 |
2001年 | 262篇 |
2000年 | 299篇 |
1999年 | 246篇 |
1998年 | 173篇 |
1997年 | 167篇 |
1996年 | 190篇 |
1995年 | 141篇 |
1994年 | 167篇 |
1993年 | 161篇 |
1992年 | 185篇 |
1991年 | 216篇 |
1990年 | 206篇 |
1989年 | 213篇 |
1988年 | 160篇 |
1987年 | 162篇 |
1986年 | 210篇 |
1985年 | 198篇 |
1984年 | 183篇 |
1983年 | 171篇 |
1982年 | 148篇 |
1981年 | 132篇 |
1980年 | 137篇 |
1979年 | 169篇 |
1978年 | 153篇 |
1977年 | 146篇 |
1976年 | 129篇 |
1975年 | 108篇 |
1974年 | 134篇 |
1973年 | 105篇 |
1971年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The information practices of collaborative interdisciplinary researchers, especially in distributed environments, remain understudied. Embracing the naturalistic paradigm, this qualitative case study relies upon semi-structured interviews, snowball sampling, and grounded analysis. Based on interviews with 53 participants from 11 Digging Into Data 3 (DID3, 2014-2016) projects, this study examines the working practices of scholars (library and information science professionals, humanists, and computer scientists) engaging in collaborative, international, data-intensive, publicly-funded interdisciplinary research. Benefits of such work include avoiding redundancy, exploding disciplinary silos, and more ambitious, larger-scale outputs. Challenges and lessons learned center on innovation, flexibility, and failure, translation, intermediaries, divisions of labor and delegation of responsibilities and tasks, conflict resolution, technology, outputs and publication, and timeframe, sustainability, and infrastructure. 相似文献
72.
Veronika Karnowski Larissa Leonhard Anna Sophie Kümpel 《Communication Research Reports》2018,35(2):91-100
Social media have become an integral part of online news use, affecting how individuals find, consume, and share news. By applying the Theory of Reasoned Action (TRA), this study investigates the effects of motives, attitude, and intention on news-sharing behavior among German social media users (n = 333). Findings show that news-sharing attitude and subjective norms have a positive effect on news-sharing intention, which in turn has a positive effect on actual news-sharing behavior. Taken together, we see that a new media behavior in the early phases of its societal diffusion—like social media news sharing in Germany in 2015—can mainly be explained by a rational choice logic and is rooted in the motives of socializing and information seeking. This finding thus reflects the double nature of social media as a means for both information retrieval and social grooming. 相似文献
73.
Social networking sites are considered a valuable resource to maintain existing friendships even over considerable distances. The present study emphasizes tie strength as a crucial determinant for the use of interactive and passive features among 302 active Facebook users and friends of different relational closeness (close friends vs. casual friends vs. acquaintances) as well as a moderator for the impact of physical distance. As expected, tie strength affected direct interaction linearly, whereas social surveillance followed a quadratic trend. Furthermore, moderation analyses revealed less frequent direct interaction between close friends and stronger surveillance of casual friends’ profiles as physical distance increases. These results indicate different functions in relationship maintenance for both behaviors as direct interaction aims at nurturing current relationships, while surveillance serves as a catalyst for promising future communications. As a consequence, physical distance influences direct interaction adversely due to emerging constraints but also contains informational value encouraging information-seeking behaviors. 相似文献
74.
Jiawei Huang Mahda M. Bagher Heather Dohn Ross Nathan Piekielek Jan Oliver Wallgrün Jiayan Zhao 《Journal of Map & Geography Libraries》2018,14(1):40-63
Libraries have been the key to preserving culture and historic legacy for centuries. One such treasure cataloged in The Pennsylvania State University (Penn State) Libraries is a collection of over 33,000 Sanborn? Fire Insurance Maps. Originally kept safe in metal drawers, the library has embarked on a journey to digitize this abundance of information, combine it with other media such as photographs, and make it accessible through a web interface. Inspired by these efforts, we accessed this information and took it to the next level. Using state of the art 3D modeling and immersive technologies, we created a historic 3D model and immersive experiences of Penn State, exemplarily for the 1922 campus. The resulting experiences can be accessed through the web but also through head mounted displays (HMDs) and mobile phones in combination with VR viewers such as the Google Cardboard. Additionally, they can be used anywhere in the world or on the campus itself as a way to enable remote and in situ experiences and learning. Immersive experiences let us connect to the past, the present and the future, and as such offer value to digital cultural heritage efforts. 相似文献
75.
The purpose of this study is to find a theoretically grounded, practically applicable and useful granularity level of an algorithmically constructed publication-level classification of research publications (ACPLC). The level addressed is the level of research topics. The methodology we propose uses synthesis papers and their reference articles to construct a baseline classification. A dataset of about 31 million publications, and their mutual citations relations, is used to obtain several ACPLCs of different granularity. Each ACPLC is compared to the baseline classification and the best performing ACPLC is identified. The results of two case studies show that the topics of the cases are closely associated with different classes of the identified ACPLC, and that these classes tend to treat only one topic. Further, the class size variation is moderate, and only a small proportion of the publications belong to very small classes. For these reasons, we conclude that the proposed methodology is suitable to determine the topic granularity level of an ACPLC and that the ACPLC identified by this methodology is useful for bibliometric analyses. 相似文献
76.
Many studies demonstrate differences in the coverage of citing publications in Google Scholar (GS) and Web of Science (WoS). Here, we examine to what extent citation data from the two databases reflect the scholarly impact of women and men differently. Our conjecture is that WoS carries an indirect gender bias in its selection criteria for citation sources that GS avoids due to criteria that are more inclusive. Using a sample of 1250 U.S. researchers in Sociology, Political Science, Economics, Cardiology and Chemistry, we examine gender differences in the average citation coverage of the two databases. We also calculate database-specific h-indices for all authors in the sample. In repeated simulations of hiring scenarios, we use these indices to examine whether women's appointment rates increase if hiring decisions rely on data from GS in lieu of WoS. We find no systematic gender differences in the citation coverage of the two databases. Further, our results indicate marginal to non-existing effects of database selection on women's success-rates in the simulations. In line with the existing literature, we find the citation coverage in WoS to be largest in Cardiology and Chemistry and smallest in Political Science and Sociology. The concordance between author-based h-indices measured by GS and WoS is largest for Chemistry followed by Cardiology, Political Science, Sociology and Economics. 相似文献
77.
Relational transgressions are emotionally difficult for those who directly experience the transgression. Less is known about how transgressions affect those located within the personal network of a relational transgression victim. This study explored how network members engaged in support marshaling in response to another’s transgression experience. Results indicate that some participants marshaled support, citing four reasons for their actions: perceived insufficiency, camaraderie, personal ramifications, and personal values. We explore these reasons for marshaling support and discuss them within the broader context of support marshaling and relational transgressions. 相似文献
78.
Joanne DiFrancisco-Donoghue William G. Werner Peter C. Douris Hallie Zwibel 《运动与健康科学(英文)》2022,11(6):725
BackgroundEsports players, like traditional athletes, practice for long hours and, thus, are vulnerable to the negative health effects of prolonged sitting. There is a lack of research on the physical activity and the health ramifications of prolonged sitting by competitive players. The purpose of this study was to investigate activity levels, body mass index (BMI), and body composition in collegiate esports players as compared to age-matched controls.MethodsTwenty-four male collegiate esports players and non-esports players between 18 and 25 years of age signed a written consent to participate. Physical activity was examined using daily activity (step count) with a wrist-worn activity tracker. A questionnaire assessing physical activity was also administered. Secondary outcomes included body-fat percentage, lean-body mass, BMI, and bone mineral content measured using dual X-ray absorptiometry.ResultsThe step count in the esports players was significantly lower than the age-matched controls (6040.2 ± 3028.6 vs. 12843.8 ± 5661.1; p = 0.004). Esports players exhibited greater body-fat percentage (p = 0.05), less lean body mass (p = 0.003), and less bone mineral content (p = 0.03), despite no difference in BMI between the esports and non-esports players.ConclusionAs compared to non-esports players, collegiate esports players were significantly less active and had a higher body-fat percentage, with lower lean body mass and bone mineral content. The BMIs showed no difference between the 2 groups. Esports athletes displayed significantly less activity and poor body composition, which are all correlated with potential health issues and risk of injury. BMI did not capture this difference and should not be considered as an accurate measure of health in competitive esports players. 相似文献
79.
[目的/意义]基于专利数据开展技术融合研究是技术融合研究的主要方式和热点方向,面向为技术融合后续研究工作开展提供参考和启发的目标,对国内外基于专利数据的技术融合研究现状进行较为全面的综述.[方法/过程]将已有研究按研究内容划分为技术融合测度及预测方法研究、特定领域/多领域间/全领域的技术融合态势测度及趋势预测、技术融合... 相似文献
80.