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   1673篇
  免费   74篇
  国内免费   38篇
电工技术   10篇
综合类   149篇
化学工业   54篇
金属工艺   19篇
机械仪表   25篇
建筑科学   115篇
矿业工程   10篇
能源动力   1篇
轻工业   51篇
水利工程   5篇
石油天然气   16篇
武器工业   1篇
无线电   41篇
一般工业技术   231篇
冶金工业   733篇
原子能技术   4篇
自动化技术   320篇
  2024年   7篇
  2023年   34篇
  2022年   52篇
  2021年   73篇
  2020年   49篇
  2019年   47篇
  2018年   42篇
  2017年   25篇
  2016年   39篇
  2015年   34篇
  2014年   61篇
  2013年   75篇
  2012年   66篇
  2011年   132篇
  2010年   111篇
  2009年   136篇
  2008年   140篇
  2007年   140篇
  2006年   120篇
  2005年   88篇
  2004年   54篇
  2003年   58篇
  2002年   44篇
  2001年   32篇
  2000年   12篇
  1999年   10篇
  1998年   7篇
  1997年   9篇
  1996年   11篇
  1995年   4篇
  1994年   13篇
  1993年   5篇
  1992年   5篇
  1991年   5篇
  1990年   4篇
  1989年   4篇
  1988年   4篇
  1987年   3篇
  1986年   2篇
  1985年   6篇
  1981年   3篇
  1979年   3篇
  1966年   1篇
  1964年   2篇
  1961年   1篇
  1959年   1篇
  1958年   2篇
  1957年   3篇
  1955年   1篇
  1954年   1篇
排序方式: 共有1785条查询结果,搜索用时 15 毫秒
121.
针对4种型号直流储能充电机控制器存在的问题,采取改进控制器、增加电池巡检仪的措施,实施效果较好。  相似文献   
122.
Theoretical models featuring cognitive processes have played a fundamental role in advancing knowledge of psychopathology and its treatment and have emphasized the importance of cognition in psychotherapy. Recognition of the importance of cognition in psychotherapy has led to a number of questions that are addressed by the articles in this special section of the Journal of Consulting and Clinical Psychology. Cognitive therapy is well represented in the articles in this special section, but therapeutic procedures that do not represent typical cognitive therapy are also examined. The articles in this special section focus on homework in the modification of cognition, cognition in the treatment of anxiety in adults and in children, change in depressive cognitions in children, cognition and rapid change in the treatment of depression, and the role of cognition in the treatment and prevention of depression that is recurrent. Examination of these types of questions holds the possibility of advances in existing treatments and the possibility of innovations in new treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
123.
The ability to select the larger of two quantities ranging from 1 to 5 (relative numerousness judgment [RNJ[) and the ability to select the larger of two pairs of quantities with each pair ranging from 1 to 8 (summation) were evaluated in young, middle-aged, and older adult orangutans (7 Pongo pygmaeus abelii and 2 Pongo pygmaeus pygmaeus). Summation accuracy and RNJ were similar to those of previous reports in apes; however, the pattern of age-related differences with regard to these tasks was different from that previously reported in gorillas. Older orangutans were less accurate than the young and middle-aged for RNJ, and summation accuracy was equivalent among age groups. Evidence was found to suggest that the young and middle-aged based their selection of the largest quantity pair on both quantities within each pair during the summation task. These results show a relationship between subject age and the quantitative abilities of adult orangutans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
124.
This study examined whether sociocontextual and sociocognitive variables explained the math/science goals of 409 Mexican American youth using a modified version of R. W. Lent, S. D. Brown, and G. Hackett's (1994) social cognitive career theory. Results from structural equation modeling indicated that the hypothesized model explained a significant amount of variance in math/science goals for both Mexican American girls and boys. Findings suggested that gender did not moderate relations among the variables in the hypothesized model. Results also suggested that most of the social cognitive career theory propositions tested were supported. Specifically, social class predicted math/science past performance accomplishments. Math/science past performance accomplishments and perceived parent support predicted math/science self-efficacy. Furthermore, math/science self-efficacy predicted math/science outcome expectations, and together with math/science interests, these sociocognitive variables predicted math/science interests and goals. Contrary to expectations, generation status, Anglo orientation, and Mexican orientation did not predict math/science past performance accomplishments, and past performance accomplishments did not predict math/science outcome expectations. Furthermore, Anglo orientation and perceived social support from parents, teachers, classmates, and a close friend did not predict math/science goals. Suggestions for future research and implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
125.
The authors investigated how 3- and 4-year-old children and adults use relative distance to judge nearbyness. Participants judged whether several blocks were by a landmark. The absolute and relative distance of the blocks from the landmark varied. In Experiment 1, judgments of nearbyness decreased as the distance from the landmark increased, particularly for 4-year-olds and adults. In Experiment 2, 4-year-olds and adults were more likely to judge objects at an intermediate distance as by the landmark when intervening objects were absent than when intervening objects were present. In Experiment 3, participants of all ages were more likely to judge objects at a short distance as by the landmark when intervening objects were absent. Reliance on relative distance to judge nearbyness becomes more systematic and applicable to larger spatial extents across development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
126.
Neuroimaging has identified an overlapping network of brain regions whose activity is modulated by mood and cognition. Studies of depressed individuals have shown changes in perception, attention, memory, and executive functions. This suggests that mood has a pervasive effect on cognition. Direct evidence of the effect of sad mood on cognition is surprisingly limited, however. Published studies have generally addressed a single cognitive ability per study because the fleeting nature of laboratory-induced mood precludes extended testing, and robust findings are limited to mood effects on memory for emotional stimuli. In this study, sad mood was induced and prolonged, enabling the effects of mood to be assessed for an array of abilities, including those that share neural substrates with sad mood and those affected by depression. Sad mood affected memory for emotional words and facial emotion recognition, but not the other processes measured, with a significant nonuniformity of effect over tasks. These results are consistent with circumscribed effects of sad mood on certain emotion-related cognitive processes, but not on cognition more generally. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
127.
Increases over birth cohorts in psychometric abilities may impact effects of aging. Data from 2 cohorts of the Long Beach Longitudinal Study, matched on age but tested 16 years apart, were modeled over ages 55-87 to test the hypothesis that the more fluid abilities of reasoning, list and text recall, and space would show larger cohort differences than vocabulary. This hypothesis was confirmed. At age 74, average performance estimates for people from the more recently born cohort were equivalent to those of people from the older cohort when they were up to 15 years younger. This finding suggests that older adults may perform like much younger ones from the previous generation on fluid measures, indicating higher levels of abilities than expected. This result could have major implications for the expected productivity of an aging workforce as well as for the quality of life of future generations. However, cohort improvements did not mitigate age declines. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
128.
The ability to maintain the separation between positive emotion and negative emotion in times of stress has been construed as a resilience mechanism. Emotional resiliency is particularly relevant in old age given concomitant declines in cognitive performance. In the present study, the authors examined the dynamical linkages among positive emotion, negative emotion, and cognition as individuals performed a complex cognitive task. Comparisons were made between younger (n = 63) and older (n = 52) age groups. Older adults manifested significant unidirectional coupling from negative emotion to cognitive performance; younger adults manifested significant unidirectional coupling from negative emotion to positive emotion and from cognitive performance to both positive and negative emotions. Implications for age differences in emotion regulatory strategies are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
129.
One of the undisputed roles of the Internet is information spreading. However, to this day there is little understanding of the interaction between the way in which information is provided on the Internet and the behavior of different human personality types. This article focuses on the impact of the need for cognition on the desired level of interactivity of a given Website and on web surfing in general. For this experiment, four commercialized Websites were used: (1) flat with no hyperlinks and no time pressure; (2) flat with time pressure; (3) interactive1 with no time pressure; and (4) interactive with time pressure. All of the Websites contained identical information presented in different ways. The relations between need for cognition as a personality variable, time pressure as a situational stressor, the interactivity of the Web site, and several demographic variables were examined on Internet users’ behavior while surfing and on their preferences. One hundred and eighty-two experienced Web surfers took part in the experiment and were randomly assigned to one of the Websites. The number of hyperlinks used while surfing were counted by specially designed software. After surfing, the participants completed questionnaires regarding their satisfaction from the site, their willingness to return to the site, how persuasive the site was, and demographic data. It was predicted that people with high need for cognition would be more experienced in the Internet, use more hyperlinks, and stay longer in the site. People with a low need for cognition were predicted to prefer interactive over linear sites. Results support the preferences of people low in need for cognition of an interactive site. Other predictions were supported only partially. Implementations for Website design and further research are discussed.  相似文献   
130.
Reviews the book, Handbook of functional neuroimaging of cognition by Roberto Cabeza and Alan Kingstone. In fairness to the contributors of this excellent volume, much of the contents deals with sober reflection on the difficulties and uncertainties of interpreting the neuroimaging data in a variety of domains such as attention, vision, semantic and episodic memory, language, and working memory. In general, the authors of this volume present a fair, sophisticated, and valuable overview of the progress (or lack thereof) that functional imaging has contributed in a variety of different domains. This book provides a sense of a field that is undergoing rapid development and that clearly will have much to offer in the future. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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