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   4408篇
  免费   76篇
  国内免费   96篇
教育   3779篇
科学研究   457篇
各国文化   8篇
体育   74篇
综合类   196篇
信息传播   66篇
  2024年   1篇
  2023年   10篇
  2022年   25篇
  2021年   42篇
  2020年   55篇
  2019年   63篇
  2018年   59篇
  2017年   53篇
  2016年   68篇
  2015年   74篇
  2014年   210篇
  2013年   273篇
  2012年   271篇
  2011年   314篇
  2010年   244篇
  2009年   242篇
  2008年   244篇
  2007年   336篇
  2006年   294篇
  2005年   240篇
  2004年   216篇
  2003年   241篇
  2002年   183篇
  2001年   186篇
  2000年   131篇
  1999年   106篇
  1998年   68篇
  1997年   81篇
  1996年   65篇
  1995年   38篇
  1994年   45篇
  1993年   17篇
  1992年   26篇
  1991年   15篇
  1990年   20篇
  1989年   11篇
  1988年   11篇
  1987年   1篇
  1957年   1篇
排序方式: 共有4580条查询结果,搜索用时 15 毫秒
131.
基于Wu-Ritt特征集方法和V.Gerdt的对合除法, 我们定义了非线性偏微分方程组的关于一般延拓方向的对合特征集 (ICS). 影响ICS方法的两个主要因素为: 延拓方向和变量的序. 本文中, 应用ICS方法处理在计算偏微分方程组的对称群过程中产生的大型偏微分方程组. 在实验的基础上, 总结了对于ICS方法较好的延拓方向和变量的序.  相似文献   
132.
本文利用算子谱的分块技巧,研究了上三角算子矩阵的谱扰动.给出了当算子A∈B(H),B∈B(K)给定时,σ(A)∪σ(B)\∩C∈B(K,H)σ(MC)的表示,这里σ(A)表示算子A的谱,MC=(AC/0B)  相似文献   
133.
The Technology Acceptance Model (TAM) is a key model describing teachers' intentions to use technology. This meta-analysis clarifies some of the contradictory findings surrounding the relations within the TAM for a sample of 45 studies comprising 300 correlations. We evaluate the overall fit of the TAM and its structural parameters, and quantify the between-sample variation through meta-analytic structural equation modeling. The TAM fitted the data well, and all structural parameters were statistically significant. On average, the TAM variables explained 39.2% of the variance in teachers' intentions to use technology. Several sample, measurement, and publication characteristics, including teachers’ experience and the representation of the TAM variables, moderated the relations within the TAM. Overall, the TAM represents a valid model explaining technology acceptance—however, the degree of explanation and the relative importance of predictors vary across samples. Implications for further research, in particular the generalizability of the TAM, are discussed.  相似文献   
134.
数学建模的思想已经渗入理科各个学科,而数学建模真正走进课堂还需要认真探讨与实践。分析了高等数学教学中结合数学建模思想的重要性与可行性,联系高等数学教学中的一个内容即微分方程问题,探讨了高等数学教学与数学建模的有机结合.  相似文献   
135.
设p为奇素数,a为整数,若ap-1≡(1mod p2),则a名为费马解。根据华罗庚给出的几个特殊的费马解,可以探求费马解的一般方法。利用初等方法及原根的性质研究同余方程xp-1≡(1modpl),l≥1的可解性,可以得到该同余方程的一切正整数解和费马解。  相似文献   
136.
通过线性函数数据建模,以偏微分方程理论为依据,使用Visual C#作为编程设计语言,通过串行通信口送入大量实验数据,并对海量数据进行实证分析,由此获取线性方程的数据建模方法,得到相应程序算法模型,在Visual C#环境下编写程序进行调试分析与测试,并详细介绍了该方法的具体设计过程,给出了关键程序代码,同时给出了利用该方法进行数据处理的一个实例。对于利用采样的海量数据获得线性函数的相关研究有一定的参考价值。  相似文献   
137.
对量子力学中的线性算符概念进行了研究,通过建立算符函数的微分学引入了超算符概念,并给出了各类超算符的定义,在此基础上利用超算符概念分析量子力学中的典型问题,结果表明超算符概念在量子力学中具有广泛的应用,且使物理意义更加清晰.  相似文献   
138.
BackgroundPrior researches have implicated a relationship of recidivism with childhood trauma (CT) and emotional intelligence (EI). However, the internal mechanism by which CT and EI influence the recidivism has not been examined.ObjectiveThis study aimed to map the road from CT and EI to recidivism in Chinese male offenders.Participants and settingThree thousand one hundred and eighty-one Chinese adult male offenders participated in this study and completed Childhood Trauma Questionnaire (CTQ) and Wong Law Emotional Intelligence Scale (WLEIS). Recidivism was quantified by the number of convictions according to official records.MethodsAfter controlling for age, education levels, family criminal history, and nature of offence, logistic regression sanalysis was performed to examine the effects of CT and EI on severity of recidivism. Structural Equation Modeling (SEM) was applied to explore the mediation model between CT, EI and recidivism.ResultsLogistic regression model shows a significant effect of CT (OR = 1.008, p < 0.01), rather than EI, on recidivism. SEM supported a full mediating effect of CT in the relationship between EI and severity of recidivism.ConclusionsOur findings suggest that EI has no direct effect on the recidivism, but exerts indirect influence on the recidivism through the mediating role of childhood trauma.  相似文献   
139.
Comparing self-perceived quality of teaching to students’ perception can be used in higher education to improve the quality of teaching of pre-service teachers in teacher education. However, comparing these measurements from different perspectives is only meaningful if the same constructs are being measured. To shed light on this comparison’s meaningfulness, we scrutinised whether aspects of quality of teaching are measured in the same way across pre-service teachers and their students by means of measurement invariance analyses. To do so, 272 pre-service teachers in teacher education rated aspects of their quality of teaching, and were rated by their 4851 students. Measurement invariance across these perspectives was tested in multilevel structural equation models. Strong measurement invariance held for two aspects of quality of teaching; for the third, one item lacked weak measurement invariance. Pre-service teachers perceived their quality of teaching lower than their students. In conclusion, aspects of quality of teaching can be compared across perspectives, and teacher education should encourage pre-service teachers to use students’ feedback as a valuable resource for improving their quality of teaching.  相似文献   
140.
利用有限差分法求解波动方程边值问题,得到了相应的稳定性分析,并进行了数值模拟.模拟结果表明;该方法求得的数值解有较高的精度和较快的运行速度.  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