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   3593篇
  免费   43篇
  国内免费   21篇
教育   2453篇
科学研究   397篇
各国文化   51篇
体育   243篇
综合类   44篇
文化理论   23篇
信息传播   446篇
  2023年   15篇
  2022年   41篇
  2021年   77篇
  2020年   123篇
  2019年   142篇
  2018年   162篇
  2017年   167篇
  2016年   147篇
  2015年   119篇
  2014年   174篇
  2013年   754篇
  2012年   159篇
  2011年   154篇
  2010年   146篇
  2009年   130篇
  2008年   127篇
  2007年   134篇
  2006年   112篇
  2005年   88篇
  2004年   53篇
  2003年   68篇
  2002年   50篇
  2001年   50篇
  2000年   44篇
  1999年   31篇
  1998年   18篇
  1997年   24篇
  1996年   22篇
  1995年   19篇
  1994年   16篇
  1993年   20篇
  1992年   14篇
  1991年   24篇
  1990年   9篇
  1989年   16篇
  1988年   10篇
  1987年   19篇
  1986年   13篇
  1985年   20篇
  1984年   12篇
  1983年   11篇
  1982年   16篇
  1981年   10篇
  1980年   10篇
  1979年   13篇
  1978年   11篇
  1977年   5篇
  1975年   7篇
  1973年   6篇
  1971年   7篇
排序方式: 共有3657条查询结果,搜索用时 9 毫秒
101.
国产十种乌头的染色体研究   总被引:1,自引:0,他引:1  
本文描述了我国产毛茛科乌头属的10个种的染色体数目和形态。  根据该属染色体基 数为8(x=8),可将这些种归为二倍体、四倍体、六倍体和八倍体种。  10种乌头的染色体在数目、大小、结构上表现出相关性。其中具根状茎而多年生的种多为二倍体,染色体形态较大,第3-7号多为近端着丝点(st)染色体, 具块茎而二年生的种多为多倍体,染色体形态较小,第3-7号多为近中着丝点(sm)染色体。染色体演化方向可能是二倍体→多倍体、大→ 小、st→sm。这进一步证明根状茎种较块茎种原始。根据染色体数目和形态,又可将这些种的染色体分为两类。这进一步支持了目前分类学上的牛扁亚属和乌头亚属的划分。本文还讨论了这些种的有关分类问题。  相似文献   
102.
Concurrent droplet charging and sorting by electrostatic actuation   总被引:1,自引:0,他引:1  
This paper presents a droplet-based microfluidic device for concurrent droplet charging and sorting by electrostatic actuation. Water-in-oil droplets can be charged on generation by synchronized electrostatic actuation. Then, simultaneously, the precharged droplets can be electrostatically steered into any designated laminar streamline, thus they can be sorted into one of multiple sorting channels one by one in a controlled fashion. In this paper, we studied the size dependence of the water droplets under various relative flow rates of water and oil. We demonstrated the concurrent charging and sorting of up to 600 droplets∕s by synchronized electrostatic actuation. Finally, we investigated optimized voltages for stable droplet charging and sorting. This is an essential enabling technology for fast, robust, and multiplexed sorting of microdroplets, and for the droplet-based microfluidic systems.  相似文献   
103.
For the last 70 years, since the establishment of the Republic of Korea, Korean education has achieved universal expansion of educational opportunity from elementary to secondary to higher education. Planning, centralized policy making, top-down implementation, and administrative control had been the standards of the first few decades of Korean education. The so-called May 31 education reform implemented in 1995 made a turning point for these approaches to education policy and administration by highlighting autonomy, openness, diversity, accountability, consumer centeredness, market control, and governance for quality education. However, these government-driven education reform initiatives have resulted in limiting the expected outcomes. In this paper, the authors call for a new approach to education policy and administration and propose supporting school innovation, empowering an internal accountability system in governance. The authors also suggest a search for normative values for democratic communitarianism as a new philosophical foundation of education policy framework, beyond instrumental values of education.  相似文献   
104.
Abstract

Over the last decade, school-based professional learning communities (PLCs) have emerged as a key feature of the education system in South Korea. To understand this relatively new phenomenon in the context of South Korea, we provide a review of research on school-based PLCs in South Korea and an empirical analysis of the Teaching and Learning International Survey (TALIS) 2008 with a focus on school-based PLCs. Based on our findings from the literature review and analysis of the TALIS, we aim to provide a fuller picture of the emerging landscape of school-based PLCs in South Korean schools. In so doing, we focus on what constitutes school-based PLCs in South Korean schools and how they are similar to and/or different from their counterparts in other countries. Implications for policy, practice, and research are discussed.  相似文献   
105.
我国教育技术起步较晚,大部分理念和技术都是从国外引入并逐步加以本土化的。国际交往对于我国教育技术的发展具有很大的作用,作为我国首次全方位关注教育技术国际交往的研究,其意义就更为重要。21世纪以来,我国教育技术领域的国际交往越来越频繁,当前的主要途径有国内师生出访交流,国外学者来华作报告、进行合作交流,对国外学者进行专访对话,学者赴外参加国际会议或国内举办国际会议,以及翻译国外著作等。10年来,随着国际合作内容不断丰富,其研究越来越广泛并走向深入,主要集中在学科发展、远程教育和学习模式等10个领域。这些国际交往使我国教育技术学科地位得到巩固和发展,研究领域得到拓展,研究方法更加科学和规范。评估10年的国际交往,今后更应加强实质性合作研究,提高交流实效,重视国际项目合作,避免停留在表面或流于形式,要以一种平等合作、批判性、包容性的态度进行国际交流和对话。  相似文献   
106.
For the dynamic demand assessment of bridge structures under ship impact loading, it may be prudent to adopt analytical models which permit rapid analysis with reasonable accuracy. Herein, a nonlinear dynamic macro-element is proposed and implemented to quantify the demand of bridge substructures subjected to ship collisions. In the proposed nonlinear macro-element, a combination of an elastic-plastic spring and a dashpot in parallel is employed to describe the mechanical behavior of ship-bows with strain rate effects. Based on the analytical model using the proposed macro-element, a typical substructure under 5000 deadweight tonnage (DWT) ship collision is discussed. Our analyses indicate that the responses of the structure using the nonlinear macro-element agree with the results from the high resolution model, but the efficiency and feasibility of the proposed method increase significantly in practical applications. Furthermore, comparisons between some current design codes (AASHTO, JTGD60-2004, and TB10002.1-2005) and the developed dynamic analysis method suggest that these design codes may be improved, at least to consider the effect of dynamic amplification on structural demand.  相似文献   
107.
ABSTRACT

Accommodating non-binary transgender people, many of whom use gender-neutral pronouns, poses a unique challenge to schools and universities, even in contexts with legal protections for transgender rights. This article explores a recent Canadian controversy around gender-neutral pronouns, and assembles a theoretical framework to analyze the argument that legal protection for transgender peoples’ pronouns poses a threat to ‘free speech.’ The framework bridges queer theory, affect theory and Deleuzo-Guattarian assemblage theory to propose a threshold between ‘extra’ and ‘excessive’ effort to accommodate social difference in everyday life. Free speech objections produce some peoples’ pronouns as requiring ‘excessive’ effort. This extra/excessive framework was exemplified by a recent Canadian social media campaign that sought to produce transgender peoples’ pronouns as requiring merely ‘extra’ effort, which entails de-politicizing pronouns. Community responses to the campaign carry significant implications for gender-expansive educational policy and practice.  相似文献   
108.
109.
Many studies examine student self-concept during compulsory schooling but few have explored the self-concept of students in higher educational settings. The current study examined self-concept by faculty and gender among higher education students in New Zealand. Participants were 929 undergraduate students from a large New Zealand university. The results showed some differences in verbal and maths self-concept by faculty. Generally, students in faculties teaching subjects more reliant on maths skills had higher maths self-concept than those in faculties where facility in verbal skills was important. The opposite results were found for verbal self-concept. No overall gender differences were found for general, academic, verbal and maths self-concept although a statistically significant difference was found for problem-solving self-concept. This finding suggests students’ choice of faculty may be based on perceptions of their skills and capabilities in the various fields, irrespective of gender.  相似文献   
110.
ABSTRACT

In Taiwan, there are service learning programs organized by older adult educational institutions that are held in high esteem. Director leadership plays a key role in the effectiveness of such institutions, and the leadership experiences of such directors in guiding service learning are worth exploring. This study conducted a qualitative approach and selected directors from eight Active Aging Learning Centers (AALCs) who achieved outstanding leadership effectiveness to take part in one-on-one and in-depth semi-structured interviews. The results indicated that: 1. Directors infused the entire service learning process with inspirational motivation by adopting through individualized consideration as a starting point. 2. When directors led the preparation process for service learning, they focused on inducing intellectual stimulation among the older adult learners, such that they felt empowered and capable of providing community services. 3. During the community service phase, directors practiced a form of leadership characterized by idealized influence to encourage, accompany, and support the elderly while they engaged in service learning. 4. The dilemma faced by directors was dissatisfaction with the leadership. Directors responded by reminding them of their original service learning intention and downplaying issues, which made the service learning group undergo a positive transformation. 5. The results of directors’ leadership had a positive effect on the community as it led to more dynamism and more people participating in community service.  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