全文获取类型
收费全文 | 3652篇 |
免费 | 64篇 |
国内免费 | 2篇 |
专业分类
教育 | 2696篇 |
科学研究 | 236篇 |
各国文化 | 34篇 |
体育 | 495篇 |
文化理论 | 74篇 |
信息传播 | 183篇 |
出版年
2023年 | 34篇 |
2022年 | 56篇 |
2021年 | 81篇 |
2020年 | 144篇 |
2019年 | 227篇 |
2018年 | 288篇 |
2017年 | 290篇 |
2016年 | 207篇 |
2015年 | 140篇 |
2014年 | 140篇 |
2013年 | 768篇 |
2012年 | 151篇 |
2011年 | 105篇 |
2010年 | 89篇 |
2009年 | 98篇 |
2008年 | 84篇 |
2007年 | 68篇 |
2006年 | 69篇 |
2005年 | 52篇 |
2004年 | 44篇 |
2003年 | 58篇 |
2002年 | 43篇 |
2001年 | 37篇 |
2000年 | 28篇 |
1999年 | 28篇 |
1998年 | 27篇 |
1997年 | 20篇 |
1996年 | 28篇 |
1995年 | 28篇 |
1994年 | 23篇 |
1993年 | 19篇 |
1992年 | 14篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 13篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 6篇 |
排序方式: 共有3718条查询结果,搜索用时 15 毫秒
991.
Fanny Dégeilh Bérengère Guillery‐Girard Jacques Dayan Malo Gaubert Gaël Chételat Pierre‐Jean Egler Jean‐Marc Baleyte Francis Eustache Armelle Viard 《Child development》2015,86(6):1966-1983
Adolescence is marked by the development of personal identity and is associated with structural and functional changes in brain regions associated with Self processing. Yet, little is known about the neural correlates of self‐reference processing and self‐reference effect in adolescents. This functional magnetic resonance imaging study consists of a self‐reference paradigm followed by a recognition test proposed to 30 healthy adolescents aged 13–18 years old. Results showed that the rostral anterior cingulate cortex is specifically involved in self‐reference processing and that this specialization develops gradually from 13 to 18 years old. The self‐reference effect is associated with increased brain activation changes during encoding, suggesting that the beneficial effect of Self on memory may occur at encoding of self‐referential information, rather than at retrieval. 相似文献
992.
Anne-Sophie Béliard 《Journalism Practice》2015,9(6):907-923
This article analyzes the emergence of TV series criticism, a recent journalistic genre in French magazines. It aims to show how dedicated fans have become professional series journalists starting in the early 1990s. The study demonstrates that this new kind of journalism challenges cultural hierarchies by legitimizing TV series as a cultural genre and distinguishing between different types of series. 相似文献
993.
Jiseok Lim Ouriel Caen Jérémy Vrignon Manfred Konrad Valérie Taly Jean-Christophe Baret 《Biomicrofluidics》2015,9(3)
Droplet-based microfluidic technologies are powerful tools for applications requiring high-throughput, for example, in biochemistry or material sciences. Several systems have been proposed for the high-throughput production of monodisperse emulsions by parallelizing multiple droplet makers. However, these systems have two main limitations: (1) they allow the use of only a single disperse phase; (2) they are based on multiple layer microfabrication techniques. We present here a pipette-and-play solution offering the possibility of manipulating simultaneously 10 different disperse phases on a single layer device. This system allows high-throughput emulsion production using aqueous flow rates of up to 26 ml/h (>110 000 drops/s) leading to emulsions with user-defined complex chemical composition. We demonstrate the multiplex capabilities of our system by measuring the kinetics of β-galactosidase in droplets using nine different concentrations of a fluorogenic substrate. 相似文献
994.
Martin Mooses Kerli Mooses Diresibachew Wondimu Haile Jérôme Durussel Priit Kaasik Yannis Paul Pitsiladis 《Journal of sports sciences》2015,33(2):136-144
The purpose of this study was to investigate the relationship between running economy (RE) and performance in a homogenous group of competitive Kenyan distance runners. Maximal aerobic capacity (VO2max) (68.8 ± 3.8 ml?kg?1?min?1) was determined on a motorised treadmill in 32 Kenyan (25.3 ± 5.0 years; IAAF performance score: 993 ± 77 p) distance runners. Leg anthropometry was assessed and moment arm of the Achilles tendon determined. While Achilles moment arm was associated with better RE (r2 = 0.30, P = 0.003) and upper leg length, total leg length and total leg length to body height ratio were correlated with running performance (r = 0.42, P = 0.025; r = 0.40, P = 0.030 and r = 0.38, P = 0.043, respectively), RE and maximal time on treadmill (tmax) were not associated with running performance (r = ?0.01, P = 0.965; r = 0.27; P = 0.189, respectively) in competitive Kenyan distance runners. The dissociation between RE and running performance in this homogenous group of runners would suggest that RE can be compensated by other factors to maintain high performance levels and is in line with the idea that RE is only one of many factors explaining elite running performance. 相似文献
995.
The architecture of microfluidic networks can significantly impact the flow distribution within its different branches and thereby influence tracer transport within the network. In this paper, we study the flow rate distribution within a network of parallel microfluidic channels with a single input and single output, using a combination of theoretical modeling and microfluidic experiments. Within the ladder network, the flow rate distribution follows a U-shaped profile, with the highest flow rate occurring in the initial and final branches. The contrast with the central branches is controlled by a single dimensionless parameter, namely, the ratio of hydrodynamic resistance between the distribution channel and the side branches. This contrast in flow rates decreases when the resistance of the side branches increases relative to the resistance of the distribution channel. When the inlet flow is composed of two parallel streams, one of which transporting a diffusing species, a concentration variation is produced within the side branches of the network. The shape of this concentration gradient is fully determined by two dimensionless parameters: the ratio of resistances, which determines the flow rate distribution, and the Péclet number, which characterizes the relative speed of diffusion and advection. Depending on the values of these two control parameters, different distribution profiles can be obtained ranging from a flat profile to a step distribution of solute, with well-distributed gradients between these two limits. Our experimental results are in agreement with our numerical model predictions, based on a simplified 2D advection-diffusion problem. Finally, two possible applications of this work are presented: the first one combines the present design with self-digitization principle to encapsulate the controlled concentration in nanoliter chambers, while the second one extends the present design to create a continuous concentration gradient within an open flow chamber. 相似文献
996.
997.
998.
José María Moreno-Jiménez Cristina Pérez-Espés Manuela Velázquez 《Government Information Quarterly》2014
Designing public policies using information technology as a communication support system is one of the most important current issues in the public policy making field. This work presents a methodology for the design and selection of public policies based on the cognitive democratic model known as e-Cognocracy. In addition to facilitating debate between representatives and the represented (deliberative democracy), this model allows for co-decision making between citizens and politicians. Furthermore, and of even greater importance, e-Cognocracy generates a process of continuing education that is concordant to the lifelong process of living systems (cognitive process). The methodology contemplates multiple rounds (usually two) when incorporating the preferences of the actors implicated in decision making and takes advantage of the creative capacity of human beings when solving complex problems. At the same time, the methodology permits the evaluation of both the individual and social learning that is derived from the scientific resolution of the problem and the democratisation of the knowledge that is extracted. This methodology was applied to a real-life experience in the Spanish municipality of Cadrete. 相似文献
999.
Daniel E. Vigo Guido Simonelli Ianina Tuñón Daniel Pérez Chada Daniel P. Cardinali Diego Golombek 《Mind, Brain, and Education》2014,8(4):175-181
Sleep in adolescents has been shown to be an important factor when looking at physical, mental, and social well‐being. Little evidence is found regarding sleep patterns in adolescents from households facing extreme poverty, where conditions such as crowding, poor housing, sanitation or education, and precarious employment set an adverse environment for sleep. In this study, we sought to assess in a nationwide sample comprised of 1,682 adolescents from Argentina, how the presence of extreme poverty—as defined by the presence of unsatisfied basic needs (UBN)—affects the relationship of sleep duration with school, work, and other daily activities. A global high prevalence of short sleeping time, a slight increase of sleep time in adolescents with UBN, and different patterns of wake activities that predict sleep deficit, depending on the presence of UBN, were found. The poor academic achievement, increased risk of accidents, and adverse health outcomes associated with sleep deprivation support the view that sleep is an additional unsatisfied basic need that worsens living conditions at this age. The results may help to design public health policies that contribute to ameliorate this adverse situation. 相似文献
1000.
M.S. Reed M. Ferré J. Martin-Ortega R. Blanche R. Lawford-Rolfe M. Dallimer J. Holden 《Research Policy》2021,50(4):104147
BackgroundInterest in impact evaluation has grown rapidly as research funders increasingly demand evidence that their investments lead to public benefits.AimsThis paper analyses literature to provide a new definition of research impact and impact evaluation, develops a typology of research impact evaluation designs, and proposes a methodological framework to guide evaluations of the significance and reach of impact that can be attributed to research.MethodAn adapted Grounded Theory Analysis of research impact evaluation frameworks drawn from cross-disciplinary peer-reviewed and grey literature.ResultsRecognizing the subjective nature of impacts as they are perceived by different groups in different times, places and cultures, we define research impact evaluation as the process of assessing the significance and reach of both positive and negative effects of research.Five types of impact evaluation design are identified encompassing a range of evaluation methods and approaches: i) experimental and statistical methods; ii) textual, oral and arts-based methods; iii) systems analysis methods; iv) indicator-based approaches; and v) evidence synthesis approaches.Our guidance enables impact evaluation design to be tailored to the aims and context of the evaluation, for example choosing a design to establish a body of research as a necessary (e.g. a significant contributing factor amongst many) or sufficient (e.g. sole, direct) cause of impact, and choosing the most appropriate evaluation design for the type of impact being evaluated.ConclusionUsing the proposed definitions, typology and methodological framework, researchers, funders and other stakeholders working across multiple disciplines can select a suitable evaluation design and methods to evidence the impact of research from any discipline. 相似文献