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   6570篇
  免费   677篇
  国内免费   472篇
  7719篇
  2024年   36篇
  2023年   166篇
  2022年   124篇
  2021年   218篇
  2020年   359篇
  2019年   370篇
  2018年   321篇
  2017年   350篇
  2016年   383篇
  2015年   271篇
  2014年   297篇
  2013年   869篇
  2012年   200篇
  2011年   275篇
  2010年   173篇
  2009年   280篇
  2008年   254篇
  2007年   272篇
  2006年   252篇
  2005年   248篇
  2004年   211篇
  2003年   183篇
  2002年   167篇
  2001年   168篇
  2000年   144篇
  1999年   122篇
  1998年   99篇
  1997年   81篇
  1996年   77篇
  1995年   86篇
  1994年   65篇
  1993年   58篇
  1992年   47篇
  1991年   48篇
  1990年   45篇
  1989年   33篇
  1988年   35篇
  1987年   33篇
  1986年   25篇
  1985年   28篇
  1984年   29篇
  1983年   18篇
  1982年   33篇
  1981年   19篇
  1980年   23篇
  1979年   28篇
  1978年   34篇
  1977年   24篇
  1976年   21篇
  1975年   10篇
排序方式: 共有7719条查询结果,搜索用时 0 毫秒
181.
《Médecine & Droit》2021,2021(169):74-80
As the first vaccines against COVID-19 arrive on the market, the question of the safety of these products arises in the public debate. The major concern is about the possible occurrence of adverse effects, particularly in the context of the use of novel pharmaceutical technologies such as mRNA. It is important to remind both patients and professionals that a vaccine is not only a medicinal product in its own right, but also a special medicinal product: biological and immunological. As a result, its supervision is draconian, and despite the urgency, no requirements have been lowered. The speed of marketing is the result both of adapted clinical trials and optimized evaluation procedures.  相似文献   
182.
Urban mobility has been severely impacted by the coronavirus pandemic, with public transport (PT) particularly affected due to infection risks and fears. The promotion of alternative modes of transport such as bike sharing systems (BSS) has gained a new drive as a possible way of providing an alternative to PT and limit a potential surge in private car use.In this study, we provide insights on the motivations for using bike sharing during the COVID-19 pandemic through a survey to the BSS users of Lisbon (entitled GIRA). Before the coronavirus pandemic, the most influential motivations were those connected to the BSS’ Service Coverage & Quality (such as the convenient location of BSS stations near the users’ destinations or the availability of shared e-bikes) as well as to the Personal Interests & Well-being of BSS users (namely the pleasure of cycling as well as the perceived environmental and health benefits). With the emergence of the COVID-19 pandemic, although the motivations of Service Coverage & Quality continue to be the most valued by respondents, the motivations associated with using BSS to avoid PT and to maintain a social distance during the trip are now as important as the motivations linked to Personal Interests & Well-being. Furthermore, new users who have joined bike sharing during COVID-19 give more importance to the Social Influence (such as seeing other people using the system or the influence of their social circle) comparatively to those who were already users before the pandemic and continue to use BSS.This research provides evidence on the importance of bike sharing to the resilience of urban transport systems, particularly during disruptive public health crises. It supports that BSS should continue to operate during the coronavirus pandemic as such systems offer a transport alternative to PT that is perceived to be capable of preserving a physical distance.  相似文献   
183.
In works of Eleanor Rosch “natural” concepts was introduced that reflect a high correlated structure of features of objects of the external world. Prototypes of the “natural” concepts are clearest cases of objects that reflect this highly correlated structure. The same high correlated structure manifested in the “natural” phenotypical classification. To formalize this highly correlated structure, we define a special type of probabilistic causal relations and then probabilistic formal concepts as a cyclically connected probabilistic causal relations. Based on these definitions, we developed a method of prototypes discovery and illustrate it on the example of digits’ prototypes discovery.  相似文献   
184.
Physical exercise is an effective tool for improving public health, but the general population exercises too little. Drawing on recent theorizing on the combined role of boredom and self-control in guiding goal-directed behavior, we test the hypothesis that individual differences in boredom and self-control differentiate high from low exercisers. The role of boredom as a non-adaptive disposition is of particular interest, because research on boredom in sports is scarce. Here, we investigate the role of such individual differences in self-reported weekly exercise behavior (in minutes) in a sample of N = 507 participants (n = 200 female, Mage = 36.43 (±9.54)). We used the robust variant of Mahalanobis distance to detect and remove n = 51 multivariate outliers and then performed latent profile analysis to assess if boredom (boredom proneness; exercise-related boredom) and self-control (trait self-control; if-then planning) combine into identifiable latent profiles. In line with theoretical considerations, the Bayesian Information Criterion favored a solution with two latent profiles. One profile was characterized by higher-than-average exercise-related boredom and boredom proneness and lower-than-average self-control and if-then planning values. This pattern was reversed for the second profile. A one-sided Bayesian two-sample t-test supported the hypothesis that the first profile is associated with less exercise behavior than the second profile, BF = 16.93. Our results foster the notion of self-control and if-then planning as adaptive dispositions. More importantly, they point to an important role of boredom in the exercise setting: exercise-related boredom and getting easily bored in general are associated with less exercise activity. This is in line with recent theorizing on boredoms' and self-controls’ function in guiding goal-directed behavior.  相似文献   
185.
ObjectivesDespite a growing body of literature on athletes' migration, the mobility and migration experiences of coaches have received limited attention. In this study, we explored the mobility and migration experiences of transnational coaches operating within the Israeli handball context.DesignA qualitative study was conducted, underpinned by our relativist ontology and a constructionist epistemological position.MethodsEight male professionals (e.g., national team coaches, senior team coaches, youth coaches), working (currently, or most recently) in national teams and clubs, who migrated to Israeli handball within the past five years were interviewed. A thematic analysis, integrating inductive and deductive reasoning, was applied in data analysis. Meticulousness was enhanced by focusing on a worthy topic, maintaining credibility, critical friends, producing generalization, and making a significant contribution.ResultsThe analysis yielded raw-data codes, further organized into lower-order themes and three higher-order themes reflecting transnational coaches' migration and mobility experiences within the Israeli handball context, including (a) cultural transition, (b) cultural adaption, and (c) coaches' personal insights about mobility and migration. The findings are conceptually analyzed and discussed in relation to the previous research on coaches' career migration.Discussion and conclusionThe findings emphasize the complexity of the migration process, accompanied by varying motivations, demands and barriers, active decision-making; all within the framework of cultural adaptation. The participants endorsed a transnational coaching career, driven by their open-mind mentality and personal-professional growth.  相似文献   
186.
多感觉整合是对不同感官信息进行选择、联系、统一乃至解释的加工过程, 它需要神经系统不同功能区域的共同投入与相互协调, 以实现多种感觉信息的时间捆绑以及全局性的预测编码。而γ神经振荡因具有反映神经皮层兴奋/抑制的平衡状况, 实现多感官信息的时间同步, 以及通过跨频耦合实现全局性预测编码的特点, 在多感觉整合的加工过程中发挥着重要作用。相比正常个体, 自闭症患者神经系统中的GABA中间神经元存在结构与功能异常, 导致γ神经振荡紊乱, 由此破坏了正常的时间同步以及预测编码加工, 并最终引发多感觉整合失调。基于上述因果关联, 未来研究可结合无创可逆性干预技术, 以γ节律神经振荡为生物反馈指标, 形成科学系统化的临床干预治疗方案。  相似文献   
187.
创造力究竟是怎么产生的, 目前尚未得出一致的结论。神经电生理技术因其高时间分辨率, 可以准确地揭示创造力产生进程中的神经振荡机制, 从而帮助人们更深刻地理解创造力的本质。近年来的研究发现, 单节律alpha神经振荡会随着创造力的增加而增强, 这反映了创造力产生过程中的内部信息加工需求增加、自上而下的抑制控制增强。同时, 多频段神经振荡交叉节律耦合体现了创造性产生过程中额叶、颞叶和顶叶等多脑区之间信息交流的动态变化。未来研究应该以整合理论框架为基础, 结合多层次多方法的研究工具, 引进更生态化的数理计算方法, 并利用计算神经科学建模来预测个体创造力发展趋势, 从而全面深刻地认识创造力的本质。  相似文献   
188.
物质丰富的时代, 如何抵御美味食物线索带来的食物渴求, 并限制饮食从而保持健康成为人们关注的重要话题之一。近年来, 国内学者为了探讨节食成功的原因, 创建中国食物图片库, 考察限制性饮食的认知神经机制, 以及成功和失败限制性饮食者的脑机制差异; 开展了特质食物渴求及中国特色的辣食渴求的认知神经研究。对推进饮食行为研究的理论发展, 也为肥胖、饮食失调等健康干预工作提供重要支持。  相似文献   
189.
The present study firstly establishes physical education (PE) teachers’ motivational profiles based on their autonomous motivation, controlled motivation and amotivation and, secondly, investigates how different PE teachers’ motivational profiles differ in terms of certain maladaptive antecedents (i.e. psychological need frustration, pressures perceived at work and burnout). It also addresses the differences in their students’ perception of autonomy support, psychological need satisfaction and autonomous motivation. A total of 105 PE teachers and their 2164 students completed validated questionnaires. Four profiles were retained in the cluster analysis. Results showed that teachers who were high on autonomous motivation displayed the most optimal pattern of outcomes, whereas teachers who were high on amotivation showed the opposite pattern. Analysis of the established profiles suggested that the experience of controlled motivation was linked with maladaptive outcomes among both teachers and students. Implications for educational policy and practice are discussed.  相似文献   
190.
近年来, 工作嵌入(Job embeddedness)作为解释员工离职和留职的新视角, 逐渐受到理论界与实务界的广泛关注和探讨。根据内容分析法(Content analysis), 系统梳理了国内外176篇工作嵌入相关文献, 分别从研究视角、内容分析和发展方向三个方面评述工作嵌入的影响结果。基于此, 总结出6种理论视角:资源保存理论、社会资本理论、计划行为理论、工作-角色依附理论、未来时间透视视角和传染过程视角。以内容分析的方式呈现关于工作嵌入研究的发展趋势和不同视角下工作嵌入影响结果的具体研究情况。未来研究应进一步构建团队工作嵌入理论模型、聚焦跨文化比较下工作嵌入的溢出效应、关注工作嵌入的双刃剑效应以及突出子维度差异化作用。  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