全文获取类型
收费全文 | 2417篇 |
免费 | 66篇 |
国内免费 | 4篇 |
专业分类
教育 | 1806篇 |
科学研究 | 118篇 |
各国文化 | 60篇 |
体育 | 246篇 |
综合类 | 1篇 |
文化理论 | 28篇 |
信息传播 | 228篇 |
出版年
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 43篇 |
2019年 | 62篇 |
2018年 | 96篇 |
2017年 | 104篇 |
2016年 | 91篇 |
2015年 | 60篇 |
2014年 | 87篇 |
2013年 | 530篇 |
2012年 | 78篇 |
2011年 | 73篇 |
2010年 | 59篇 |
2009年 | 69篇 |
2008年 | 86篇 |
2007年 | 63篇 |
2006年 | 69篇 |
2005年 | 61篇 |
2004年 | 46篇 |
2003年 | 62篇 |
2002年 | 64篇 |
2001年 | 43篇 |
2000年 | 31篇 |
1999年 | 35篇 |
1998年 | 22篇 |
1997年 | 36篇 |
1996年 | 36篇 |
1995年 | 35篇 |
1994年 | 19篇 |
1993年 | 21篇 |
1992年 | 22篇 |
1991年 | 31篇 |
1990年 | 20篇 |
1989年 | 25篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 24篇 |
1985年 | 16篇 |
1984年 | 15篇 |
1983年 | 19篇 |
1982年 | 25篇 |
1981年 | 18篇 |
1980年 | 8篇 |
1979年 | 23篇 |
1978年 | 9篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1974年 | 7篇 |
1972年 | 6篇 |
1967年 | 5篇 |
排序方式: 共有2487条查询结果,搜索用时 15 毫秒
91.
92.
Stephen P. Timoshenko 《Journal of The Franklin Institute》1943,235(4):327-349
93.
The highly unsteady flow around a rowing blade in motion is examined using a three-dimensional computational fluid dynamics
(CFD) model which accounts for the interaction of the blade with the free surface of the water. The model is validated using
previous experimental results for quarter-scale blades held stationary near the surface in a water flume. Steady-state drag
and lift coefficients from the quarter-scale blade flume simulation are compared to those from a simulation of the more realistic
case of a full-scale blade in open water. The model is then modified to accommodate blade motion by simulating the unsteady
motion of the rowing shell moving through the water, and the sweep of the oar blade with respect to the shell. Qualitatively,
the motion of the free surface around the blade during a stroke shows a realistic agreement with the actual deformation encountered
during rowing. Drag and lift coefficients calculated for the blade during a stroke show that the transient hydrodynamic behaviour
of the blade in motion differs substantially from the stationary case. 相似文献
94.
In this case study, the Russell Corporation's acquisition of Spalding creates an opportunity for Spalding's marketing staff to reevaluate their licensing strategy. Prior ownership has heavily leveraged the equity of the Spalding brand to generate maximum licensing revenues with a minimal concern for the long-term impact on the brand. Placed in the position of Spalding's Vice President for Marketing, the reader must grapple with strategic licensing factors such as the rise of the big-box retailer in distribution channels and product category congruence across extensions. Ultimately, with several licensing contracts up for renewal, a decision on the future direction of the Spalding brand must be outlined and defended in a presentation to the executives at Russell. 相似文献
95.
BackgroundIndividuals with diabetes have greater central arterial stiffness, wave reflections, and hemodynamics, all of which promote the accelerated cardiovascular pathology seen in this population. Acute aerobic exercise has been shown to be an effective strategy for reducing central arterial stiffness, wave reflections, and hemodynamics in healthy individuals; however, the effects of acute aerobic exercise in reducing these outcomes is not well established in people with diabetes. Recently, implementation of high-intensity interval exercise (HIIE) has shown superior improvements in cardiovascular health outcomes when compared to traditional aerobic exercise. Yet, the effect of HIIE on the aforementioned outcomes in people with diabetes is not known. The purpose of this study was to (i) describe the central arterial stiffness, wave reflections, and hemodynamic responses to a bout of HIIE and moderate-intensity continuous exercise (MICE) in adults with diabetes; and (ii) compare the effects of HIIE and MICE on the aforementioned outcomes.MethodsA total of 24 adult men and women (aged 29–59 years old) with type 1 (n = 12) and type 2 (n = 12) diabetes participated in a randomized cross-over study. All participants completed the following protocols: (i) HIIE: cycling for 4 × 4 min at 85%–95% of heart rate peak (HRpeak), interspersed with 3 min of active recovery at 60%–70%HRpeak; (ii) MICE: 33 min of continuous cycling at 60%–70%HRpeak; and (iii) control (CON): lying quietly in a supine position for 30 min.ResultsA significant group × time effect was found for changes in central systolic blood pressure (F = 3.20, p = 0.01) with a transient reduction for the HIIE group but not for the MICE or CON groups. There was a significant group × time effect for changes in augmentation index at a heart rate of 75 beats/min (F = 2.32, p = 0.04) with a decrease following for HIIE and MICE but not for CON. For all other measures of central arterial stiffness and hemodynamics, no significant changes were observed (p > 0.05).ConclusionA bout of HIIE appears to lead to a greater transient reduction in central systolic blood pressure than the reduction observed following MICE; however, both HIIE and MICE improved augmentation index at a heart rate of 75 beats/min in people with diabetes. There was no significant difference in response to HIIE and MICE in all outcomes. This provides preliminary evidence on the role of HIIE on such outcomes in people with diabetes. 相似文献
96.
97.
Evaluating the Comparability of Paper‐ and Computer‐Based Science Tests Across Sex and SES Subgroups
As access and reliance on technology continue to increase, so does the use of computerized testing for admissions, licensure/certification, and accountability exams. Nonetheless, full computer‐based test (CBT) implementation can be difficult due to limited resources. As a result, some testing programs offer both CBT and paper‐based test (PBT) administration formats. In such situations, evidence that scores obtained from different formats are comparable must be gathered. In this study, we illustrate how contemporary statistical methods can be used to provide evidence regarding the comparability of CBT and PBT scores at the total test score and item levels. Specifically, we looked at the invariance of test structure and item functioning across test administration mode across subgroups of students defined by SES and sex. Multiple replications of both confirmatory factor analysis and Rasch differential item functioning analyses were used to assess invariance at the factorial and item levels. Results revealed a unidimensional construct with moderate statistical support for strong factorial‐level invariance across SES subgroups, and moderate support of invariance across sex. Issues involved in applying these analyses to future evaluations of the comparability of scores from different versions of a test are discussed. 相似文献
98.
99.
This paper draws upon critical discourse analysis, cultural studies and communication theory, studies on media and educational reform, and the work of Bernstein, Bourdieu and Luhmann in particular, to explore how the print and media ‘mediated’ a period of educational change marked by moves to self‐management in schools in Victoria, Australia. It considers how the media was mobilized by various education stakeholders, and in turn informed relations between schools and government, through policy discourses and texts. It considers why and how particular themes became media ‘issues’, how schools and teachers responded to these issues, and how the media was used by various stakeholders in education to shape policy debates. It is based on a year‐long qualitative study that explored critical incidents and representations about education in the print media over a year in the daily press. It illustrates the ways in which a neo‐liberal Victorian government mobilized the media to gain strategic advantage to promote radical education reform policies, considers the media effects of this media/tion process on schools and teachers, and conceptualizes how school and system performance is fed from and into media representations, public perceptions and community understandings of schools and teachers' work. 相似文献
100.
In this paper we question whether the radical change in the life situation of people with learning difficulties triggered by the closure of long‐stay hospitals does in fact represent an adequate inclusion into civil society or whether people with learning difficulties continue to experience strong exclusionary tendencies. We will explore the implications of a range of contemporary social justice theories for people with learning difficulties and examine the justice inherent in arrangements for training people with learning difficulties made by Local Enterprise Companies (LECs). We argue that training may be seen as a crucible of social values since its distribution transmits powerful messages about who is considered salvageable or unsalvageable, who is likely to become economically active and who is to be consigned to some special status of otherness. Finally, we consider what conceptualizations of social justice might hold out most hope for people with learning difficulties. 相似文献