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   232篇
  免费   1篇
  国内免费   8篇
教育   173篇
科学研究   34篇
各国文化   3篇
体育   10篇
综合类   9篇
文化理论   1篇
信息传播   11篇
  2024年   1篇
  2023年   3篇
  2022年   6篇
  2021年   10篇
  2020年   13篇
  2019年   11篇
  2018年   8篇
  2017年   9篇
  2016年   5篇
  2015年   4篇
  2014年   13篇
  2013年   23篇
  2012年   8篇
  2011年   12篇
  2010年   11篇
  2009年   11篇
  2008年   22篇
  2007年   13篇
  2006年   10篇
  2005年   9篇
  2004年   16篇
  2003年   4篇
  2002年   2篇
  2001年   3篇
  2000年   3篇
  1999年   3篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1989年   1篇
排序方式: 共有241条查询结果,搜索用时 15 毫秒
1.
基于混合索引的中文全文检索系统研究   总被引:1,自引:0,他引:1  
在中文全文检索系统中引入了混合索引,建立了混合索引之Hash索引,给出了Hash索引在内存中的存储结构,并给出了这种索引下的检索算法。这种索引既能保证索引的全面性,又能提高系统检索效率。通过实际构建系统,探讨了基于混合索引的中文全文检索系统的实现。  相似文献   
2.
Despite recent evidence that students in public schools significantly outperform their private school counterparts, private schooling continues to account for approximately 40% of secondary school enrolments in Indonesia. In an effort to explain this sustained demand, we combine analyses of PISA data with in-country interviews and school visits. Ultimately, we find that although government dependent private schools are underfunded with a high proportion of uncertified, underpaid teachers (with limited access to training and professional development), demand remains high due to their focus on religious training and education, as well as their ability to increase educational access for low-income families.  相似文献   
3.
在文献[1]中提出的谱分解估计是一种在线性混合模型中同时估计固定效应和方差分量的新方法.在本文中,我们对带有两个方差分量的线性混合模型进行了谱分解估计和方差分析估计的比较.得出了方差分量的这两种估计在某些条件下方差相等,而且谱分解估计具有一些方差分析估计的最优性.  相似文献   
4.
WOMBAT is a software package for quantitative genetic analyses of continuous traits, fitting a linear, mixed model; estimates of covariance components and the resulting genetic parameters are obtained by restricted maximum likelihood. A wide range of models, comprising numerous traits, multiple fixed and random effects, selected genetic covariance structures, random regression models and reduced rank estimation are accommodated. WOMBAT employs up-to-date numerical and computational methods. Together with the use of efficient compilers, this generates fast executable programs, suitable for large scale analyses. Use of WOMBAT is illustrated for a bivariate analysis. The package consists of the executable program, available for LINUX and WINDOWS environments, manual and a set of worked example, and can be downloaded free of charge from http://agbu. une.edu.au/~kmeyer/wombat.html  相似文献   
5.
This mixed-methods study examined the experiences of belonging/otherness among Arab teachers in Israel. A group of boundary-crossing teachers: Arab teachers in Jewish schools (AJ; N = 57) was compared with Arab teachers teaching in their own community (AA; N = 103). We found that the AJ group had a multicultural orientation, unlike the AA group, who were community-orientated. These orientations are reflected in different otherness sources, different motivations for selecting a workplace, and differences in identity ratings. While professional and social sources promoted teachers’ sense of belonging in the two groups, the source of AJs' sense of otherness was the national divide as opposed to community-oriented aspects in AAs. Selfefficacy ratings were high in both groups with a significant advantage for AJs, an unanticipated finding given that most of them were women, had attended teacher training colleges rather than universities, and were rarely homeroom teachers. Arab teachers' involvement in Jewish schools was partial with a low proportion of classroom educators or teachers in managerial roles. AJs tend to leave their national identity outside the school, and are not involved in political discourse or in the staffroom power relations. The phenomenon of integrating AJs is relatively new, and within a segregated education system that limits the opportunities for Jews and Arabs to meet, it can provide a viable, albeit limited, tool to inhibit prejudice and antagonism between Jews and Arabs.  相似文献   
6.
7.
利用遥感手段,以低廉的成本有效获取包括居民地在内的地表信息是促使卫星遥感数据转化为现实生产力的根本所在,也是遥感应用领域中亟待解决的重要课题。目前虽然已有"空间分辨率越高,遥感分类精度也越高"的共性认识,但是遥感影像空间分辨率的不同对于城镇和乡村这两种不同类型的居民地信息提取产生怎样的影响等,目前尚无明确答案。本文首先以同一区域不同空间分辨率的4种卫星遥感影像数据为信息源,定性探讨居民地在不同分辨率遥感影像上的表现特征;然后以两种不同分辨率的影像ALOS和TM为实验对象,对这两种影像上城镇和乡村居民地信息提取精度进行比较分析。结果显示:虽然基于10m-ALOS影像的居民地信息提取精度较30m-TM影像约提高6.09%,并且无论是依据哪一种空间分辨率的遥感影像,城镇居民地的信息提取精度都明显高于乡村居民地,但是,对于分散式分布的乡村居民地,遥感影像空间分辨率的下降令其遥感识别更容易受到周边环境的影响,其信息提取精度会随着遥感影像空间分辨率的增加而显著提高;相比之下,城镇居民地的信息提取精度随遥感影像空间分辨率增加的趋势是有限的。造成这一现象的原因主要在于虽然居民地的轮廓清晰性以及像元的纯净度都与遥感影像的空间分辨率基本上呈正相关,但是空间分辨率的提高会放大居民地内部结构的细节,从而对居民地的遥感识别与信息提取工作增加一些干扰性的噪声信息。  相似文献   
8.
丙烯菊酯农药的微生物生物修复作用研究   总被引:3,自引:0,他引:3  
通过富集驯化培养,获得了降解丙烯菊酯的混合微生物.研究结果表明,该混合微生物发挥最优降解力的温度是35℃,pH为7.0,培养时间为72h.丙烯菊酯降解速度和混合培养微生物生长速度对外加碳源有较强的依赖性.在培养液中添加1g/L葡萄糖时,72h丙烯菊酯去除率可达76%;而采用丙烯菊酯作为培养菌生长的唯一碳源、氮源和能源时,72h丙烯菊酯去除率为55%.  相似文献   
9.
小鼠经 1 0天灌喂中药合剂后 ,安静时小鼠肌 MDA值明显降低 ,GSH值升高。力竭运动后 GSH、ATP、MDA值的恢复明显加快 ,其中 GSH值的加快提示 ,在恢复期内 GSH的变化可能对肌肉机能的恢复有重要意义。  相似文献   
10.
In two recent articles, Nicholas Dixon has argued that the intent to hurt and injure opponents which is essential to mixed martial arts (MMA) makes the sport intrinsically immoral. Although bondage, domination, sadism, and masochism (BDSM) also involves the intentional infliction of pain and injury, Dixon argues that it is morally permissible in many cases. In this paper, I examine the principle underlying Dixon's differentiation of MMA and BDSM. I argue that, when properly elaborated, that principle does not in fact condemn MMA as intrinsically immoral, but rather implies that the attitudes and actions of most autonomously consenting amateur MMA fighters and some autonomously consenting professionals are prima facie morally permissible.  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