全文获取类型
收费全文 | 223篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
教育 | 175篇 |
科学研究 | 15篇 |
各国文化 | 3篇 |
体育 | 19篇 |
文化理论 | 1篇 |
信息传播 | 14篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 11篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 40篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 13篇 |
2006年 | 3篇 |
2005年 | 8篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1958年 | 1篇 |
1940年 | 1篇 |
1938年 | 1篇 |
1923年 | 1篇 |
1920年 | 1篇 |
1870年 | 1篇 |
排序方式: 共有227条查询结果,搜索用时 31 毫秒
121.
Hao Wu Zhanqing Li Hanqing Li Kun Luo Yuying Wang Peng Yan Fei Hu Fang Zhang Yele Sun Dongjie Shang Chunsheng Liang Dongmei Zhang Jing Wei Tong Wu Xiaoai Jin Xinxin Fan Maureen Cribb Marc L Fischer Markku Kulmala Tuukka Petj 《国家科学评论(英文版)》2021,8(3)
A new mechanism of new particle formation (NPF) is investigated using comprehensive measurements of aerosol physicochemical quantities and meteorological variables made in three continents, including Beijing, China; the Southern Great Plains site in the USA; and SMEAR II Station in Hyytiälä, Finland. Despite the considerably different emissions of chemical species among the sites, a common relationship was found between the characteristics of NPF and the stability intensity. The stability parameter (ζ = Z/L, where Z is the height above ground and L is the Monin–Obukhov length) is found to play an important role; it drops significantly before NPF as the atmosphere becomes more unstable, which may serve as an indicator of nucleation bursts. As the atmosphere becomes unstable, the NPF duration is closely related to the tendency for turbulence development, which influences the evolution of the condensation sink. Presumably, the unstable atmosphere may dilute pre-existing particles, effectively reducing the condensation sink, especially at coarse mode to foster nucleation. This new mechanism is confirmed by model simulations using a molecular dynamic model that mimics the impact of turbulence development on nucleation by inducing and intensifying homogeneous nucleation events. 相似文献
122.
Hanna Schleihauf Esther Herrmann Julia Fischer Jan M. Engelmann 《Child development》2022,93(4):1072-1089
We investigate how the ability to respond appropriately to reasons provided in discourse develops in young children. In Study 1 (N = 58, Germany, 26 girls), 4- and 5-, but not 3-year-old children, differentiated good from bad reasons. In Study 2 (N = 131, Germany, 64 girls), 4- and 5-year-old children considered both the strength of evidence for their initial belief and the quality of socially provided reasons for an alternative view when deciding whether to change their minds. Study 3 (N = 80, the United States, 42 girls, preregistered) shows that 4- and 5-year-old children also consider meta-reasons (reasons about reasons) in their belief revision. These results suggest that by age 4, children possess key critical thinking capacities for participating in public discourse. 相似文献
123.
Nonprofit organizations' constituents, trustees and donors find financial reports confusing and too detailed. Advocates of Service Efforts and Accomplishments and assessment measures suggest that disclosing both financial and nonfinancial indicators will make the reports more useful. With hundreds of possible measures, ratios and data available, the nonprofit manager must select measures that portray the institution's condition and performance. This article presents a process and rationale for determining the measures. Also presented is a set of measures developed from interviews with presidents and administrators which were selected by a quantitative process that models complex decisions. The information selected for display both describes and measures the organization's condition and performance. 相似文献
124.
125.
Albrecht Fischer 《Endeavour》1981,5(4):152-157
Many sporting activities reflect new technological developments, sometimes to the extent of creating new industries. Among the most striking is hang-gliding, now so popular that the production of the necessary equipment is the fastest growing branch of the aviation industry in the USA. The design of the ultra-light aircraft involves important aerodynamic principles and novel methods of construction. This article reviews the development of hang gliding and the type of equipment in current use. 相似文献
126.
Fischer H 《Child abuse & neglect》2003,27(12):1339; author reply 1341-1339; author reply 1343
127.
Martin Wimmer Pia Ehrnlechner Armin Fischer Alfons Kemper 《Informatik - Forschung und Entwicklung》2005,92(3):167-181
Die plattformunabh?ngige und organisationsübergreifende Web Services-Interoperabilit?t setzt ein leistungsf?higes und flexibles
Autorisierungssystem voraus. In diesem Beitrag wird ein Zugriffskontrollsystem vorgestellt, welches sich durch das Zusammenspiel
lokaler und verteilter Autorisierung auszeichnet. Im Zusammenhang mit lokaler Zugriffskontrolle, bei der Rechte innerhalb
einer Organisation ausgewertet werden, stellt sich insbesondere die Herausforderung, Autorisierungsregeln zu konsolidieren:
Da die Funktionalit?t von Web Services h?ufig auf weitere Anwendungen und Betriebsmittel wie Datenbanksystemen aufsetzt, ergeben
sich Abh?ngigkeiten bezüglich der Autorisierung, die überprüft und eingehalten werden müssen. über eine verteilte Zugriffskontrolle
wird der Aufbau von Kollaborationsnetzwerken erm?glicht. Der Augenmerk liegt im Folgenden auf schwach gekoppelten Zusammenschlüssen,
die die Autonomie der beteiligten Organisationen beibeh?lt. Skalierbarkeit und Effizenz werden durch den Einsatz von rollenbasierter
Zugriffskontrolle einerseits und dem Caching ?hnlicher, wiederkehrender Autorisierungen andererseits erreicht. 相似文献
128.
Fischer Jean-Paul Sander Emmanuel Sensevy Gérard Vilette Bruno Richard Jean-François 《European Journal of Psychology of Education - EJPE》2019,34(2):439-456
European Journal of Psychology of Education - Ensuring students correctly understand the notion of equality is a fundamental problem in teaching mathematics. Is it possible to teach arithmetic in... 相似文献
129.
130.