首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6523篇
  免费   90篇
  国内免费   5篇
教育   4433篇
科学研究   764篇
各国文化   47篇
体育   591篇
文化理论   28篇
信息传播   755篇
  2022年   39篇
  2021年   64篇
  2020年   101篇
  2019年   156篇
  2018年   190篇
  2017年   198篇
  2016年   188篇
  2015年   114篇
  2014年   157篇
  2013年   1099篇
  2012年   150篇
  2011年   151篇
  2010年   134篇
  2009年   124篇
  2008年   155篇
  2007年   154篇
  2006年   116篇
  2005年   107篇
  2004年   94篇
  2003年   89篇
  2002年   94篇
  2001年   121篇
  2000年   143篇
  1999年   130篇
  1998年   62篇
  1997年   55篇
  1996年   70篇
  1995年   60篇
  1994年   62篇
  1993年   53篇
  1992年   112篇
  1991年   96篇
  1990年   87篇
  1989年   123篇
  1988年   78篇
  1987年   75篇
  1986年   80篇
  1985年   101篇
  1984年   73篇
  1983年   74篇
  1982年   76篇
  1981年   62篇
  1980年   67篇
  1979年   80篇
  1978年   79篇
  1977年   61篇
  1976年   64篇
  1974年   51篇
  1973年   45篇
  1969年   44篇
排序方式: 共有6618条查询结果,搜索用时 15 毫秒
991.
992.
Double-block instruction has become a popular strategy for supporting struggling mathematics students in algebra I. Despite its widespread adoption, little consistent evidence supports the attributes of a successful double-block design or the effectiveness of this instructional strategy. In this study, the authors examine a pilot implementation of a double-block strategy—instantiated in the program Intensified Algebra—that combines core algebra content with insights from research on how students learn mathematics and explicit noncognitive supports focused on key attitudes, beliefs, and behaviors essential to student success. The results of the study show that, when implemented with fidelity, participation in the program significantly increased student achievement on the state end-of-course algebra I assessment.  相似文献   
993.
In view of recent changes in the higher education sector, such as increased tuition fees, a greater focus has been placed on widening participation initiatives and monitoring student satisfaction. The aims of the current study were twofold: (1) to explore whether pre-entry programmes foster successful transition to higher education, and (2) to examine longitudinally the factors associated with course satisfaction. Eighty-eight first-year psychology students completed a questionnaire measuring academic self-efficacy, social identity and student satisfaction at the start (Time 1, November 2015) and end (Time 2, March 2016) of the academic year. Findings indicated that students who participated in a pre-entry programme reported higher academic self-efficacy and satisfaction compared to typical route students. Moreover, academic self-efficacy predicted student satisfaction at the start of the academic year, whereas in-group affect (a facet of social identity) predicted this at the end of the academic year. The current findings indicate that pre-entry programmes may have a positive impact on students’ sense of academic self-efficacy. On a more general level, the findings also suggest that academic self-efficacy and social identity may be key indicators of student satisfaction. This highlights the complexities of the concept of ‘student satisfaction’, and demonstrates the utility of examining multiple factors relating to student satisfaction across different time points.  相似文献   
994.
This article contests the narrative of Chinese international students (internationals for short) as passive and problematic to reveal the complexity and fluidity of their experiences. Simultaneously, it troubles the overly linear approach of stage theory in understanding internationals’ adjustment. Following nine first- and nine second-year students in US colleges over a year and involving them in semi-structured interviews and journal prompts, this research examined how they evolved. Findings show that while participants grew on academic and personal fronts, their experiences remained multi-dimensional, with second years being less sanguine and reporting challenges different from first years. This article argues that seeing Chinese internationals’ evolution as an uneven ascent affords a more nuanced understanding compared to a U-shape stage theory as it recognizes that while internationals are evolving, new situations provide challenges which they learn to overcome. Consequently, Chinese internationals’ growth troubles the deficit discourse around them and departs from pre-existing research around postgraduates. Findings spell implications for how the college community should enhance transcultural understanding and how future research around internationals could develop.  相似文献   
995.
This paper presents a fixed-time observer for a general class of linear time-delay systems. In contrast to many existing observers, which normally estimate system’s trajectory in an asymptotic fashion, the proposed observer estimates system’s state in a prescribed time. The proposed fixed-time observer is realized by updating the observer in an impulsive manner. Simulation results are also presented to illustrate the convergence behavior of the proposed fixed-time observer.  相似文献   
996.
In this paper we develop a new framework for time series segmentation based on a Hierarchical Linear Dynamical System (HLDS), and test its performance on monophonic and polyphonic musical note recognition. The center piece of our approach is the inclusion of constraints in the filter topology, instead of on the cost function as normally done in machine learning. Just by slowing down the dynamics of the top layer of an augmented (multilayer) state model, which is still compatible with the recursive update equation proposed originally by Kalman, the system learns directly from data all the musical notes, without labels, effectively creating a time series clustering algorithm that does not require segmentation. We analyze the HLDS properties and show that it provides better classification accuracy compared to current state-of-the-art approaches.  相似文献   
997.
In this paper, we analyze detection of multilevel phase-shift keying (MPSK) signals transmitted over a Gamma shadowed Nakagami-m fading channel. We derive novel analytical expression, in terms of Meijer’s G function, for Fourier coefficients of the probability density function of the received signal composite phase. Under the assumption of the imperfect reference signal extraction in the receiver, which is performed from the pilot signal, the analytical expression is derived for the symbol error probability (SEP) in the form of convergent series. The existence of the error floor is identified, and expression for its computation is provided. Mathematical proofs for convergence of Fourier series are provided for both SEP and SEP floor, and novel expressions of upper bounds for truncation errors are derived in terms of elementary mathematical functions. The convergence rate of the derived expressions is examined. Numerical results are confirmed independently by Monte-Carlo simulations.  相似文献   
998.
To spur technology transfer, emerging market policymakers often require foreign firms to form joint ventures (JVs) with domestic firms. Through knowledge spillovers, JVs may reduce technology acquisition costs for domestic firms. Yet domestic firm rents from JVs could discourage innovation through a cannibalization effect. Which force dominates is an empirical question. I address it with novel data on China's auto sector. In response to fuel economy standards requiring firms to upgrade technology or sacrifice quality, firms with JVs reduced quality and price relative to their counterparts. Consistent with cannibalization, firms with JVs drive the negative effect.  相似文献   
999.
Whilst previous research has highlighted significant relationships between golfers’ clubhead velocity (CHV) and their vertical jump height and maximum strength, these field-based protocols were unable to measure the actual vertical ground reaction force (vGRF) variables that may correlate to performance. The aim of this study was to investigate relationships between isometric mid-thigh pull (IMTP), countermovement jump (CMJ), squat jump (SJ) and drop jump (DJ) vGRF variables and CHV in highly skilled golfers. Twenty-seven male category 1 golfers performed IMTP, CMJ, SJ and DJ on a dual force platform. The vertical jumps were used to measure positive impulse during different stretch-shortening cycle velocities, with the IMTP assessing peak force (PF) and rate of force development (RFD). Clubhead velocity was measured using a TrackMan launch monitor at a golf driving range. Pearsons correlation coefficient analyses revealed significant relationships between peak CHV and CMJ positive impulse (r = 0.788, < 0.001), SJ positive impulse (r = 0.692; < 0.001), DJ positive impulse (r = 0.561, < 0.01), PF (r = 0.482, < 0.01), RFD from 0–150 ms (r = 0.343, < 0.05) and RFD from 0–200 ms (r = 0.398, < 0.05). The findings from this investigation indicate strong relationships between vertical ground reaction force variables and clubhead velocity.  相似文献   
1000.
In an increasingly differentiated culture of movement, play and sport as well as a more and more digitized society, the topic of eSports has been intensively discussed in recent time. The objective-categorical basics of the discussion seem to be clear only at first sight. A closer look points to the need of a differentiated cross-disciplinary discussion of the topic. It becomes clear that above all the underlying understanding of sport, the content-related demarcation as well as the social positioning contribute decisively to the perception of eSport (approval/rejection). The present article takes up the discussion with reference to the heterogeneity, heteronomy and complexity of sports and provides an alternative interpretive idea on the topic.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号