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   2458篇
  免费   51篇
  国内免费   6篇
电工技术   16篇
综合类   1篇
化学工业   448篇
金属工艺   49篇
机械仪表   51篇
建筑科学   117篇
矿业工程   7篇
能源动力   48篇
轻工业   208篇
水利工程   35篇
石油天然气   1篇
无线电   264篇
一般工业技术   381篇
冶金工业   579篇
原子能技术   17篇
自动化技术   293篇
  2021年   23篇
  2020年   19篇
  2019年   27篇
  2018年   32篇
  2017年   26篇
  2016年   51篇
  2015年   26篇
  2014年   49篇
  2013年   116篇
  2012年   78篇
  2011年   139篇
  2010年   80篇
  2009年   81篇
  2008年   105篇
  2007年   108篇
  2006年   104篇
  2005年   110篇
  2004年   78篇
  2003年   66篇
  2002年   70篇
  2001年   58篇
  2000年   50篇
  1999年   55篇
  1998年   105篇
  1997年   69篇
  1996年   73篇
  1995年   44篇
  1994年   46篇
  1993年   31篇
  1992年   34篇
  1991年   22篇
  1990年   34篇
  1989年   37篇
  1988年   34篇
  1987年   27篇
  1986年   32篇
  1985年   43篇
  1984年   34篇
  1983年   36篇
  1982年   27篇
  1981年   21篇
  1980年   18篇
  1979年   17篇
  1978年   23篇
  1977年   19篇
  1976年   22篇
  1975年   23篇
  1974年   20篇
  1973年   15篇
  1971年   11篇
排序方式: 共有2515条查询结果,搜索用时 15 毫秒
171.
The influences of modeling and social feedback on the acquisition of writing revision were studied with 72 college students. Students watching a coping female model gradually improving her writing technique on a sentence-combining task were hypothesized to surpass students observing a mastery model perform the technique flawlessly on a writing-skill measure and an array of self-regulatory measures, such as self-satisfaction reactions, self-efficacy perceptions, and intrinsic interest in the task. Students observing a mastery model were expected, in turn, to surpass those learning without the benefit of modeling on these same measures. Support for both hypotheses was found. Social feedback during enactive performance assisted learners from all modeling groups in acquiring writing and self-regulatory skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
172.
173.
174.
We previously introduced a vacuum deposition interface for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF MS) on a moving surface (e.g., quartz wheel, Mylar tape, metal target). In our present work, the approach has been extended to demonstrate parallel analysis for multiple on-line infusion MALDI MS and capillary array electrophoresis (CAE)-MALDI MS. In the infusion mode, individual peptide samples were simultaneously deposited on a Mylar tape cartridge using an array of eight capillaries, yielding eight parallel traces. For CAE-MALDI/TOF MS, the same number of separation capillaries were coupled with an array of eight infusion capillaries using a common liquid junction, containing matrix solution. A fast-scanning mirror was employed to traverse the beam of the desorption laser across the Mylar tape to probe one trace at a time. The positions of the eight sample traces formed on the tape were automatically determined, and all samples were analyzed in rapid sequence using a kilohertz repetition rate laser and a high-throughput data acquisition system. The instrumentation was operated with CAE MS for high-throughput analysis without compromising data quality. The principles of parallel separation-vacuum deposition should be generally applicable to MALDI/TOF MS analysis for proteomics and other areas where separation and high throughput are required.  相似文献   
175.
The American Psychological Association has done little to empower the nuclear freeze resolution (NFR) adopted in 1982. The general debate on the issues of advocacy, competency, and ethics should be suspended so that the issues associated specifically with the NFR can be resolved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
176.
The Rorschach Comprehensive System has been considered by W. M. Grove and R. C. Barden (1999) as inadmissible for expert psychological testimony according to the guidelines from the Daubert (1993), Joiner (1997), and Kumho (1999) decisions. This article refutes W. M. Grove and R. C. Barden's conclusions, arguing that the Rorschach Comprehensive System is (a) testable, (b) valid and reliable, (c) extensively peer reviewed, (d) associated with a reasonable error rate, (e) standardized, (f) accepted by a relevant and substantial scientific community, and (g) appropriate for a wide range of forensic issues. In drawing their negative conclusions, W. A Grove and R. C. Barden overlooked or minimized a substantial body of empirical data supporting the reliability and validity of the Rorschach Comprehensive System and misinterpreted the language and intent of the Supreme Court decisions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
177.
Self-presentations are more likely to be internalized when they can be justified as representative of self. As predicted, when the behavior fell in their latitude of acceptance rather than rejection, Ss with strong prior self-beliefs (defined by self-perceived behavioral variability on the trait dimension) took greater responsibility for their self-perceptions, viewed them as more justifiable, and changed their later self-appraisals more. In contrast, Ss with weak prior self-beliefs were more influenced by extreme self-presentations (in the latitude of rejection) and viewed their behavior as equally justifiable irrespective of the latitude in which it fell. It was also found that negative arousal plays a role in guiding people's reactions to out-of-character behavior. These findings have implications for conceptualizations of the self-concept (e.g., as stable vs. unstable) and the relation between the private and public sides of self. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
178.
 XCS [1, 2] represents a new form of learning classifier system [3] that uses accuracy as a means of guiding fitness for selection within a Genetic Algorithm. The combination of accuracy-based selection and a dynamic niche-based deletion mechanism achieve a long sought-after goal–the reliable production, maintenance, and proliferation of the sub-population of optimally general accurate classifiers that map the problem domain [4]. Wilson [2] and Lanzi [5, 6] have demonstrated the applicability of XCS to the identification of the optimal action-chain leading to the optimum trade-off between reward distance and magnitude. However, Lanzi [6] also demonstrated that XCS has difficulty in finding an optimal solution to the long action-chain environment Woods-14 [7]. Whilst these findings have shed some light on the ability of XCS to form long action-chains, they have not provided a systematic and, above all, controlled investigation of the limits of XCS learning within multiple-step environments. In this investigation a set of confounding variables in such problems are identified. These are controlled using carefully constructed FSW environments [8, 9] of increasing length. Whilst investigations demonstrate that XCS is able to establish the optimal sub-population [O] [4] when generalisation is not used, it is shown that the introduction of generalisation introduces low bounds on the length of action-chains that can be identified and chosen between to find the optimal pathway. Where these bounds are reached a form of over-generalisation caused by the formation of dominant classifiers can occur. This form is further investigated and the Domination Hypothesis introduced to explain its formation and preservation.  相似文献   
179.
180.
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