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   1155篇
  免费   24篇
  国内免费   44篇
教育   821篇
科学研究   305篇
各国文化   1篇
体育   16篇
综合类   22篇
文化理论   1篇
信息传播   57篇
  2023年   4篇
  2022年   23篇
  2021年   35篇
  2020年   36篇
  2019年   18篇
  2018年   8篇
  2017年   8篇
  2016年   6篇
  2015年   20篇
  2014年   87篇
  2013年   90篇
  2012年   147篇
  2011年   155篇
  2010年   117篇
  2009年   105篇
  2008年   56篇
  2007年   105篇
  2006年   77篇
  2005年   64篇
  2004年   34篇
  2003年   21篇
  2002年   2篇
  2000年   3篇
  1999年   1篇
  1990年   1篇
排序方式: 共有1223条查询结果,搜索用时 15 毫秒
1.
《中华人民共和国民法典》第1198条增列了体育场馆的安全保障义务,但其具体判断标准仍不明确,且与自甘风险的关系存疑。确立体育安全保障义务的标准,应以合标准的硬件设施、有序的组织服务和合理救助义务为基础考量要素,以体育类型和项目特点为个性考量要素,注重体育安保义务的个性化。第1176条第2款与第1198条适用关系不明,其一方面存在内在价值体系缺陷,另一方面存在外在文义、逻辑体系缺陷。解释论上应以自甘风险的内在价值体系为进路,参加者风险自担,活动组织者尽到体育安保义务时不应再承担公平责任,活动组织者因一般过失未尽到安全保障义务时应对其减责,活动组织者因故意或重大过失未尽到安全保障义务时不应对其减责。  相似文献   
2.
本文旨在通过对思政课程的规范性设置、思政课程与文化素质教育相结合的重要性和“社会教师”对于思政课程的促进作用进行分析,深入剖析思政课程的现状和所面对的挑战,分析改革的必要性和有效途径。  相似文献   
3.
The frequent occurrence of security incidents in ride-sharing is a challenge for the survival of IT-enabled ride-sharing platforms. Passengers’ protective behavior is an effective means to alleviate this issue, with benefits to both the passengers and the platforms. This study explores the mechanisms of passengers’ protective behavior in the ride-sharing context by combining protection motivation theory (PMT) and usage situation theory. We test our hypotheses using data (n = 346) collected from a field survey based on a real scenario. The findings reveal that PMT and usage situation theory work well to explain passengers’ protective behavior during ride-sharing. This study explains the motivation behind passengers’ protective behavior in the ride-sharing context, extends the contents of PMT by exploring its antecedents, and extends the contents of usage situation theory by introducing a new dimension. Our findings can help ride-sharing platforms take appropriate strategies to improve passengers’ protective behavior.  相似文献   
4.
Cui  Yangfeng  Ma  Zhe  Ma  Guiqiu  Sheng  Jing 《天津大学学报(英文版)》2020,26(1):33-39
In this work,air plasma surface treatment followed by oxidation in an atmospheric environment was used to generate activated low-density polyethylene(LDPE) with oxygen-containing functional groups and peroxide radicals.The resulting samples were then studied by using attenuated total internal reflectance-Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,and the 2,2-diphenyl-1-picrylhydrazyl method.Peroxide radicals are generally considered active substances which can initiate the crosslinking reaction.Melt mixing of the surface-treated LDPE allowed activated polymer chains with peroxide radicals to initiate the crosslinking reaction,and the maximum gel fraction obtained was 4.1%.The rheological behaviors,including viscosity,storage and loss moduli,loss tangent,and Cole-Cole plots,of the slightly crosslinked LDPE were studied,and the results of tensile experiments revealed that the formation of slightly crosslinked structures can improve yield and fracture stresses without sacrificing the breakage strain.  相似文献   
5.
[目的/意义]对在线负面评论有用性影响因素分析,能够有助于揭示在线评论的作用机理,更加有效地发挥在线评论的应用价值。[过程/方法]以京东商城(jd.com)搜索型和体验型商品的在线负面评论为研究对象建立分层回归模型,从形式特征、内容特征、文本特征、反馈特征等4个维度出发,探索不同因素对在线负面评论有用性的影响,并采用主成分分析法对商品类型调节作用下的影响因素重要程度进行排序。[结果/结论]研究结果表明,在线负面评论的影响因素受商品类型调节,会对有用性产生非线性复杂影响,导致作用度存在差异。对于搜索型商品,在线负面评论中评论等级、回复次数和评论长度等影响因素的有用性明显;而对于体验型商品,在线负面评论中附加图片、详尽地客观描述能够促进消费者做出购买决策。  相似文献   
6.
In this paper, a multi-model switching control is developed for air-breathing hypersonic vehicle with variable geometry inlet(AHV-VGI). A variable geometry inlet with the translating cowl is adopted to capture the enough air mass flow for the scramjet engine, which can ensure a more powerful thrust. However, the using of VGI causes the unknown changes of the aerodynamics and thrust, making the model of AHV more complex. Therefore, we firstly analyze the thrust characteristic with the translating cowl and present the conception of optimal elongation distance of translating cowl(EDTC). Consequently, multiple different nonlinear aerodynamic models are constructed by curve fitting for each position of the translating cowl. Then, a switching mechanism dependent on EDTC is proposed and the adaptive RBF neural controllers are designed for velocity subsystem and altitude system of every model. Furthermore, the common Lyapunov functional is constructed to prove the stability of the multi-model switching process. Finally, numerical simulations are given to demonstrate the effectiveness of the proposed control approach for AHV-VGI.  相似文献   
7.
智慧学习、智慧课堂、智慧校园等智慧教育的具象形态,从本质上来说,就是算法学习、算法课堂、算法校园,这也使得算法教育治理日益成为教育现代化进程中不可忽略的研究议题。遵循"技术逻辑→风险挑战→公共政策"的分析框架对算法教育治理进行系统探讨,发现由于数据鸿沟、算法黑箱、效率优先等众多因素的复合影响,导致算法教育存在自我强化偏差、技术控制困境、主体性危机等治理难题,也让教育公平、教育平等、教育效率等传统议题在"互联网+教育"时代显得更加突出。为规避只注重相关关系描述,而不重视因果关系研究的算法给教育带来的风险挑战,可从算法教育基础的数据正义、算法教育程序的合理公开、算法教育结果的有限使用等三个层面开展对算法教育治理的公共政策选择,以更好地推动人工智能在实现发展更加公平更有质量教育过程中的重要作用。  相似文献   
8.
9.
We investigate a novel perspective to the development of effective algorithms for contact recommendation in social networks, where the problem consists of automatically predicting people that a given user may wish or benefit from connecting to in the network. Specifically, we explore the connection between contact recommendation and the text information retrieval (IR) task, by investigating the adaptation of IR models (classical and supervised) for recommending people in social networks, using only the structure of these networks.We first explore the use of adapted unsupervised IR models as direct standalone recommender systems. Seeking additional effectiveness enhancements, we further explore the use of IR models as neighbor selection methods, in place of common similarity measures, in user-based and item-based nearest-neighbors (kNN) collaborative filtering approaches. On top of this, we investigate the application of learning to rank approaches borrowed from text IR to achieve additional improvements.We report thorough experiments over data obtained from Twitter and Facebook where we observe that IR models, particularly BM25, are competitive compared to state-of-the art contact recommendation methods. We provide further empirical analysis of the additional effectiveness that can be achieved by the integration of IR models into kNN and learning to rank schemes. Our research shows that the IR models are effective in three roles: as direct contact recommenders, as neighbor selectors in collaborative filtering and as samplers and features in learning to rank.  相似文献   
10.
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