全文获取类型
收费全文 | 2873篇 |
免费 | 41篇 |
国内免费 | 23篇 |
专业分类
教育 | 1796篇 |
科学研究 | 338篇 |
各国文化 | 32篇 |
体育 | 502篇 |
综合类 | 6篇 |
文化理论 | 33篇 |
信息传播 | 230篇 |
出版年
2023年 | 20篇 |
2022年 | 39篇 |
2021年 | 66篇 |
2020年 | 73篇 |
2019年 | 106篇 |
2018年 | 141篇 |
2017年 | 158篇 |
2016年 | 135篇 |
2015年 | 79篇 |
2014年 | 105篇 |
2013年 | 377篇 |
2012年 | 122篇 |
2011年 | 118篇 |
2010年 | 122篇 |
2009年 | 95篇 |
2008年 | 103篇 |
2007年 | 93篇 |
2006年 | 93篇 |
2005年 | 86篇 |
2004年 | 62篇 |
2003年 | 56篇 |
2002年 | 64篇 |
2001年 | 59篇 |
2000年 | 45篇 |
1999年 | 49篇 |
1998年 | 27篇 |
1997年 | 23篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 23篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 15篇 |
1986年 | 16篇 |
1985年 | 22篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1975年 | 21篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1971年 | 10篇 |
排序方式: 共有2937条查询结果,搜索用时 31 毫秒
31.
32.
面对学生的错误,传统的做法是直接把正确的答案教给学生,因为这样可以节省教学时间,增加课堂训练的密度和强度.但评讲不久便发现,错误又死灰复燃,许多同学依然重复"昨天的故事".究其原因,由于这种评讲没有切入学生解题时犯错的真实情境,评讲缺乏针对性,教学的低效性自然也就显现出来了. 相似文献
33.
Birgit Angelika Schmidt Martin Andreas Ziemann Simone Pentzien Toralf Gabsch Werner Koch Jörg Krüger 《文物保护研究》2016,61(2):113-122
A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified. 相似文献
34.
There is a crisis of valuation practices in the current academic life sciences, triggered by unsustainable growth and “hyper-competition.” Quantitative metrics in evaluating researchers are seen as replacing deeper considerations of the quality and novelty of work, as well as substantive care for the societal implications of research. Junior researchers are frequently mentioned as those most strongly affected by these dynamics. However, their own perceptions of these issues are much less frequently considered. This paper aims at contributing to a better understanding of the interplay between how research is valued and how young researchers learn to live, work and produce knowledge within academia. We thus analyze how PhD students and postdocs in the Austrian life sciences ascribe worth to people, objects and practices as they talk about their own present and future lives in research. We draw on literature from the field of valuation studies and its interest in how actors refer to different forms of valuation to account for their actions. We explore how young researchers are socialized into different valuation practices in different stages of their growing into science. Introducing the concept of “regimes of valuation” we show that PhD students relate to a wider evaluative repertoire while postdocs base their decisions on one dominant regime of valuing research. In conclusion, we discuss the implications of these findings for the epistemic and social development of the life sciences, and for other scientific fields. 相似文献
35.
36.
Lennart Fischer Joseph Baker Rebecca Rienhoff Bernd Strauß Judith Tirp Dirk Büsch 《Journal of sports sciences》2016,34(17):1637-1642
There is little research investigating the maintenance of perceptual-cognitive expertise in general and even less comparing coaches of different ages. The aim of this study was to test for perceptual-cognitive differences between age groups, licence levels, and their interaction. This study investigated differences in skilled performance between young and middle-aged coaches of three different skill levels. Participants performed an accuracy-oriented pattern recall (mean distance in pixel) and a time-oriented flicker test (mean detection time in ms). There were some significant differences between age groups and between skill groups for both tests, but no interactions. For the pattern recall test, the effect sizes were larger for skill level differences, while for the flicker test effects were larger for ageing. These results suggest coaches are able to maintain accuracy skills better than reaction timed tasks. This is in line with findings on speeded performance in general populations, which show declines with age. Moreover, results also support findings on perceptual expertise in skills where accuracy was important. 相似文献
37.
Thomas Steiner Beat Müller Thomas Maier Jon Peter Wehrlin 《Journal of sports sciences》2016,34(15):1438-1444
The purpose of this study was to analyse the effect of bike type – the 26-inch-wheel bike (26“ bike) and the 29-inch-wheel bike (29“ bike) – on performance in elite mountain bikers. Ten Swiss National Team athletes (seven males, three females) completed six trials with individual start on a simulated cross-country course with 35 min of active recovery between trials (three trials on a 26“ bike and three trials on a 29“ bike, alternate order, randomised start-bike). The course consisted of two separate sections expected to favour either the 29“ bike (section A) or the 26“ bike (section B). For each trial performance, power output, cadence and heart rate were recorded and athletes’ experiences were documented. Mean overall performance (time: 304 ± 27 s vs. 311 ± 29 s; P < 0.01) and performance in sections A (P < 0.001) and B (P < 0.05) were better when using the 29“ bike. No significant differences were observed for power output, cadence or heart rate. Athletes rated the 29“ bike as better for performance in general, passing obstacles and traction. The 29“ bike supports superior performance for elite mountain bikers, even on sections supposed to favour the 26“ bike. 相似文献
38.
The main purpose of this article is to advance an alternative perspective on the relationship between intrinsic and extrinsic motivation, and in particular to examine critically the assertion that these processes are antagonistic such that the will to learn for its own sake is inhibited by the presence of extrinsic, tangible rewards and incentives such as school grades. The presumption of an antagonistic relationship largely depends on the theoretical perspective adopted. An alternative interpretation based on need achievement theory leads to distinctly different conclusions. Exploring this new perspective allows one to identify both the conditions under which intrinsic motives may coexist with extrinsic motives as well as to consider some of the means by which intrinsic motives and caring about learning can be stimulated in their own right in school settings. 相似文献
39.
Anne Focke Sina Spancken Christian Stockinger Benjamin Thürer Thorsten Stein 《European Journal of Sport Science》2016,16(7):787-793
Benefits of bilateral practice both for the non-dominant and for the dominant body side have been shown in several studies. Thereby, most of the studies included movement tasks of the upper extremity or investigated sports games in which the ability of acting bilaterally is an essential basis for success and, thus, a bilateral practice is reasonable anyway. Individual unilaterally performed sports including movement tasks of the lower extremity are rarely investigated. Therefore, the aim of our study was to test if contralateral transfer due to bilateral practice can be found in an unilaterally performed sport including the lower extremity. We trained and tested 61 adolescent athletes in long jump to compare the jumping performance of the dominant leg after a 12-week practice period between two groups: a bilateral practice group that practiced specific long jump exercises with both the dominant and non-dominant leg and an unilateral practice group that practiced specific long jump exercises only with the dominant leg. Results showed a superior effect of bilateral practice compared to unilateral practice regarding the jumping performance of the dominant leg. The performance increase at post-test and retention-test for the dominant limb was significantly higher for the bilateral practice group (pre-to-post: 5.2%, pre-to-retention: 7.4%) compared to the unilateral practice group (pre-to-post: 3.4%, pre-to-retention: 4.5%). Thus, bilateral practice should be established in the early practice programmes of track and field athletes to improve the performance of the dominant take-off leg. 相似文献
40.
This paper addresses a dynamic portfolio investment problem. It discusses how we can dynamically choose candidate assets, achieve the possible maximum revenue and reduce the risk to the minimum level. The paper generalizes Markowitz's portfolio selection theory and Sharpe's rule for investment decision. An analytical solution is presented to show how an institutional or individual investor can combine Markowitz's portfolio selection theory, generalized Sharpe's rule and Value-at-Risk(VaR) to find candidate assets and optimal level of position sizes for investment (dis-investment). The result shows that the generalized Markowitz's portfolio selection theory and generalized Sharpe's rule improve decision making for investment. 相似文献