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   1421篇
  免费   72篇
  国内免费   4篇
电工技术   15篇
综合类   1篇
化学工业   352篇
金属工艺   25篇
机械仪表   21篇
建筑科学   52篇
矿业工程   12篇
能源动力   49篇
轻工业   79篇
水利工程   8篇
石油天然气   12篇
无线电   109篇
一般工业技术   389篇
冶金工业   98篇
原子能技术   28篇
自动化技术   247篇
  2024年   2篇
  2023年   17篇
  2022年   32篇
  2021年   51篇
  2020年   34篇
  2019年   36篇
  2018年   35篇
  2017年   50篇
  2016年   39篇
  2015年   47篇
  2014年   63篇
  2013年   117篇
  2012年   88篇
  2011年   112篇
  2010年   69篇
  2009年   53篇
  2008年   88篇
  2007年   79篇
  2006年   61篇
  2005年   57篇
  2004年   37篇
  2003年   51篇
  2002年   43篇
  2001年   18篇
  2000年   13篇
  1999年   15篇
  1998年   15篇
  1997年   19篇
  1996年   14篇
  1995年   13篇
  1994年   15篇
  1993年   14篇
  1992年   8篇
  1991年   9篇
  1990年   5篇
  1989年   11篇
  1987年   3篇
  1986年   4篇
  1985年   2篇
  1984年   7篇
  1983年   7篇
  1982年   6篇
  1981年   2篇
  1980年   4篇
  1979年   8篇
  1978年   2篇
  1976年   4篇
  1971年   5篇
  1969年   2篇
  1954年   1篇
排序方式: 共有1497条查询结果,搜索用时 15 毫秒
1.
At times, people keep their emotions from showing during social interactions. The authors' analysis suggests that such expressive suppression should disrupt communication and increase stress levels. To test this hypothesis, the authors conducted 2 studies in which unacquainted pairs of women discussed an upsetting topic. In Study 1, one member of each pair was randomly assigned to (a) suppress her emotional behavior, (b) respond naturally, or (c) cognitively reappraise in a way that reduced emotional responding. Suppression alone disrupted communication and magnified blood pressure responses in the suppressors' partners. In Study 2, suppression had a negative impact on the regulators' emotional experience and increased blood pressure in both regulators and their partners. Suppression also reduced rapport and inhibited relationship formation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
There is widespread application of indicators to the assessment of environmental condition of streams. These indicators are intended for use by managers in making various comparative and absolute assessments and often have a role in resource allocation and performance assessment. Therefore, the problem of formally defining confidence in the results is important but difficult because the sampling strategies used are commonly based on a compromise between the requirements of statistical rigour and the pragmatic issues of access and resources. It is rare to see this compromise explicitly considered and consequently there is seldom quantification of the uncertainty that could affect the confidence a manager has in an indicator. In this paper, we present a method for quantitatively assessing the tradeoffs between sampling density and uncertainty in meeting various monitoring objectives. Assessments using judgement‐based representative reaches are shown to be unreliable; instead a sampling approach is recommended based on the random selection of measuring sites. A detailed dataset was collected along two streams in Victoria, Australia, and the effect of sampling density was assessed by subsampling from this dataset with precision related to the number of sites assessed per reach length and the intensity of the sampling at each site. The sampling scheme to achieve a given precision is shown to depend on the monitoring objective. In particular, three objectives were considered: (1) making a baseline assessment of current condition; (2) change detection; and (3) detection of a critical threshold in condition. Change detection is shown to be more demanding than assessing baseline condition with additional sampling effort required to achieve the same precision. Sampling to detect a critical threshold depends on nominating acceptable values of Type I and II error and the size of the effect to be detected. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
3.
This paper analyses the load influence on a d.c. drive motor servo system for all six degrees of freedom of industrial robots with an articulated configuration. Through the analyses, the analytical equations of total inertia and gravitation moments of an industrial robot servo system for external coordinate function were obtained. A mathematical model of an electro-mechanical industrial robot system was also developed.  相似文献   
4.
随着广播、电信和IT业的融合,未来的电话和数字电视都将成为互联网上的应用,这样就需要采用新型的客户端设备(CPE)和网络基础设施,以适应更高数据传输速率的要求,并满足新出现的DVB—T/S/C标准以及符合当前和提议中的通讯要求。  相似文献   
5.
6.
In this work we investigated the mechanism of the electrochemical intercalation reactions in rf sputtered nickel oxide thin films electrodes by two techniques: mechanical stress change measurements by means of an optical technique and mass changes using an electrochemical quartz microbalance (EQCM). The experiments were performed in alkaline electrolytes containing cations of the first column of the periodic table. Reversible mass and volume changes were observed. In order to explain these experimental results, an exchange reaction is proposed, in which the oxidation process is accompanied by the deinteractional of a relative large number of “light” cations, simultaneously with the intercalation of a smaller number of heaviest cations.  相似文献   
7.
8.
9.
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