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   27840篇
  免费   239篇
  国内免费   11篇
教育   20048篇
科学研究   3139篇
各国文化   169篇
体育   1628篇
综合类   19篇
文化理论   575篇
信息传播   2512篇
  2022年   101篇
  2021年   168篇
  2020年   267篇
  2019年   379篇
  2018年   2627篇
  2017年   2569篇
  2016年   2026篇
  2015年   438篇
  2014年   581篇
  2013年   3024篇
  2012年   632篇
  2011年   1127篇
  2010年   1201篇
  2009年   753篇
  2008年   993篇
  2007年   1504篇
  2006年   418篇
  2005年   686篇
  2004年   767篇
  2003年   646篇
  2002年   409篇
  2001年   360篇
  2000年   404篇
  1999年   301篇
  1998年   190篇
  1997年   229篇
  1996年   200篇
  1995年   140篇
  1994年   154篇
  1993年   147篇
  1992年   214篇
  1991年   215篇
  1990年   239篇
  1989年   242篇
  1988年   208篇
  1987年   220篇
  1986年   195篇
  1985年   222篇
  1984年   172篇
  1983年   155篇
  1982年   143篇
  1981年   113篇
  1980年   116篇
  1979年   198篇
  1978年   136篇
  1977年   120篇
  1976年   101篇
  1975年   98篇
  1974年   108篇
  1973年   104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
In this paper a summary is given of the various processes which have been proposed for making the potash in the natural silicates available as a fertilizer.Experimental trials of a new rotary kiln process for treating feldspar are described, which depends upon a previous treatment before furnacing, consisting of a method of aggregating or clumping the mix so that chemical contact of the reacting substances is brought about during the subsequent processing. The qualitative and quantitative results obtained on a number of experimental trials on a mill scale of operation are presented and discussed. It is shown that it is possible to economically manufacture a potash fertilizer containing free lime from feldspar, and for a sufficiently low cost to make an industry based upon the method worthy of consideration.  相似文献   
73.
The most frequently requested accommodation among students with learning disabilities (LD) in postsecondary settings is extended test time. The frequency with which this accommodation is requested and granted compels disability service providers to become knowledgeable about the factors that influence the need for, and appropriateness of, the accommodation. Moreover, the synthesis of these factors becomes the basis for determining if the accommodation is reasonable under federal law. The purpose of this article is to present a step‐by‐step model to be used as a decision‐making process when considering the accommodation of extended test time for postsecondary students with LD. The model is designed to assist disability service providers in the analysis and synthesis of information collected from (1) the student's diagnostic evaluation, (2) the course or classroom test to be accommodated, and (3) student interviews. A list of diagnostic tests from the four most frequently administered test batteries used with adults is provided, along with a concise explanation of how characteristics of LD impact reading, writing, and math, and relate to the need for extended time. This information can be used to determine if extended test time is a reasonable accommodation and to estimate how much additional time to provide.  相似文献   
74.
75.
76.
77.
The aim was to examine cross-cultural variation in linguistic responsiveness to young children in 10 English-speaking mother–child dyads and 10 Italian-speaking mother– child dyads. All 20 children were late talkers who possessed delays in expressive vocabulary development but age-appropriate cognitive and receptive language skills. Dyads were filmed in 15 minute free play contexts, which were transcribed and coded for measures of maternal linguistic input (e.g. rate, MLU, labels, expansions) and child language productivity (e.g. utterances, different words used). The results revealed that the Italian mothers used more utterances, spoke more quickly and used a more diverse vocabulary than the Canadian mothers. The Italian children mirrored their mothers and also used more utterances and a more diverse vocabulary than the Canadian children. Mothers in both groups used similar percentages of responsive labels and expansions. However, Italian mothers responded to fewer of their children's vocalisations, using a smaller percentage of imitations and interpretations than the Canadian mothers. Correlations between maternal input and children's language productivity revealed that contingent language measures (e.g. imitations, interpretations, expansions) were related to high levels of productivity in children in both cultural groups. The results support the use of language interventions based on increasing maternal responsiveness for these children at the one-word stage of language development. They also point to differences that may be culturally based. For example, Italian mothers use faster rates of interaction and appear to have higher expectations for their children's verbal participation in interaction. This is reflected in higher rates of language production from their children, even though children in both cultural groups have similar vocabulary sizes.  相似文献   
78.
79.
80.
Working Graphs     
  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