全文获取类型
收费全文 | 4374篇 |
免费 | 151篇 |
国内免费 | 63篇 |
专业分类
电工技术 | 90篇 |
技术理论 | 1篇 |
综合类 | 1110篇 |
化学工业 | 85篇 |
金属工艺 | 24篇 |
机械仪表 | 32篇 |
建筑科学 | 606篇 |
矿业工程 | 136篇 |
能源动力 | 49篇 |
轻工业 | 69篇 |
水利工程 | 74篇 |
石油天然气 | 50篇 |
武器工业 | 6篇 |
无线电 | 55篇 |
一般工业技术 | 204篇 |
冶金工业 | 1673篇 |
原子能技术 | 7篇 |
自动化技术 | 317篇 |
出版年
2023年 | 17篇 |
2022年 | 26篇 |
2021年 | 56篇 |
2020年 | 59篇 |
2019年 | 64篇 |
2018年 | 43篇 |
2017年 | 58篇 |
2016年 | 85篇 |
2015年 | 73篇 |
2014年 | 174篇 |
2013年 | 167篇 |
2012年 | 178篇 |
2011年 | 229篇 |
2010年 | 245篇 |
2009年 | 261篇 |
2008年 | 228篇 |
2007年 | 299篇 |
2006年 | 293篇 |
2005年 | 300篇 |
2004年 | 257篇 |
2003年 | 282篇 |
2002年 | 229篇 |
2001年 | 168篇 |
2000年 | 90篇 |
1999年 | 70篇 |
1998年 | 39篇 |
1997年 | 23篇 |
1996年 | 31篇 |
1995年 | 24篇 |
1994年 | 18篇 |
1993年 | 13篇 |
1990年 | 12篇 |
1988年 | 15篇 |
1987年 | 15篇 |
1984年 | 10篇 |
1971年 | 13篇 |
1970年 | 13篇 |
1966年 | 14篇 |
1965年 | 49篇 |
1964年 | 26篇 |
1963年 | 14篇 |
1962年 | 23篇 |
1961年 | 20篇 |
1960年 | 16篇 |
1959年 | 24篇 |
1958年 | 17篇 |
1957年 | 23篇 |
1956年 | 19篇 |
1955年 | 24篇 |
1954年 | 23篇 |
排序方式: 共有4588条查询结果,搜索用时 15 毫秒
1.
Adult neurogenesis is a highly regulated process during which new neurons are generated from neural stem cells in two discrete regions of the adult brain: the subventricular zone of the lateral ventricle and the subgranular zone of the dentate gyrus in the hippocampus. Defects of adult hippocampal neurogenesis have been linked to cognitive decline and dysfunction during natural aging and in neurodegenerative diseases, as well as psychological stress-induced mood disorders. Understanding the mechanisms and pathways that regulate adult neurogenesis is crucial to improving preventative measures and therapies for these conditions. Accumulating evidence shows that mitochondria directly regulate various steps and phases of adult neurogenesis. This review summarizes recent findings on how mitochondrial metabolism, dynamics, and reactive oxygen species control several aspects of adult neural stem cell function and their differentiation to newborn neurons. It also discusses the importance of autophagy for adult neurogenesis, and how mitochondrial and autophagic dysfunction may contribute to cognitive defects and stress-induced mood disorders by compromising adult neurogenesis. Finally, I suggest possible ways to target mitochondrial function as a strategy for stem cell-based interventions and treatments for cognitive and mood disorders. 相似文献
2.
心理测试的根本目的是为了让人们在测试过程中,产生某些特定行为,即个体对测试题目的反应,并根据这些行为反应来推论其相应的心理特性。在一定程度上帮助我们了解人类的心理活动,并从中得到帮助。因此,本文对基于学生群体心理测试系统的设计进行深入研究。 相似文献
3.
4.
基于承包商预期收益不变的不平衡报价模型 总被引:1,自引:0,他引:1
在招标实践中,通常采用最低价中标原则,使得投标人不得不压低其投标价格。基于承包商预期收益不变的不平衡报价模型,是在“工程量清单报价”的条件下,考虑到施工中工程量的变化及施工顺序的影响,体现了资金的时间价值,在保持承包商预期收益不变的前提下,通过调整各分项工程的单价,来降低工程报价,以增加中标机会而建立的。所建立的模型简单,易于操作,并配以具体的工程实例,通过计算机求得其最优解,可供承包商投标报价时参考。 相似文献
5.
Does life satisfaction moderate the effects of stressful life events on psychopathological behavior during adolescence? 总被引:1,自引:0,他引:1
Psychologists within a positive psychology framework have proposed the existence of a set of psychological strengths that buffer against the development of psychopathology. To date, most research efforts in positive psychology have focused on adults. This longitudinal study tested the prediction that adolescents' judgments of life satisfaction moderate the influence of stressful life events on the subsequent development of psychopathological behavior. Using a sample of 816 middle and high school students, the study demonstrated support for the moderational model for externalizing behavior outcomes, but not internalizing behavior problems. Specifically, adolescents with positive life satisfaction (vs. those who were dissatisfied with their lives) were less likely to develop later externalizing behaviors in the face of stressful life events. The study also revealed that adolescent life satisfaction reports show moderate stability across a one-year time frame and independently predict subsequent externalizing behavior even while controlling for prior levels of externalizing behavior... (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
6.
Hannerz Harald; Albertsen Karen; Nielsen Martin Lindhardt; Tüchsen Finn; Burr Hermann 《Canadian Metallurgical Quarterly》2004,23(3):283
This study explored whether factors related to the work environment could predict changes in body mass index (BMI) and whether the effect of psychosocial factors was dependent on baseline BMI. The sample consisted of 1,980 male employees from the Danish National Work Environment Cohort Study. Changes in BMI between 1995 and 2000 were analyzed, by multiple regression, as a function of background variables and a series of occupational variables obtained in 1995. Age, baseline BMI, job insecurity, and psychological demands predicted changes in BMI. Job insecurity and high or low psychological demands increased the likelihood of weight gain among obese employees, whereas they increased the likelihood of weight loss among employees with a low BMI. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
This article proposes a model of the ways in which dyadic interactions between employees who occupy 1 of 4 archetypal social roles in organizations can lead to either episodic or institutionalized patterns of victimization. The model shows how the occurrence of victimization involving these 4 role types is influenced by organizational variables such as power differences, culture, and access to social capital. The model integrates behavioral and social structural antecedents of victimization to develop a relational perspective on the dynamics of harmful behavior in the workplace. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Reviews the book, Constructing the subject: Historical origins of psychological research by Kurt Danziger (1990). Kurt Danziger's Constructing the Subject: Historical Origins of Psychological Research is a book of singular importance because it provides such a penetrating analysis, and does so in a manner that is cause for considerable reflection. In brief, Danziger provides a history lesson that not only situates the names and the projects of experimental psychology in the first part of this century, but also aims to clarify the project of knowledge generation both past and present. Indeed, shades of Quine, Kuhn, and Hesse permeate this book in a way that demands psychologists examine their own investigative practices and logics of justification. Through Wundt, through Galton, through Ebbinghaus and others, Danziger illuminates the development of experimental psychology along with the historical and philosophical vicissitudes that have given rise to numerous psychological knowledge claims. If it is true that we must understand our history in order to understand our present, then Danziger's book should be required reading in all research laboratories. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Ryba Nancy L.; Cooper Virginia G.; Zapf Patricia A. 《Canadian Metallurgical Quarterly》2003,34(5):499
What is the current standard of practice for evaluations of juvenile competence to stand trial (JCST)? The present study surveyed psychologists regarding the practices used when conducting JCST evaluations. Respondents rated the importance of 17 elements that might be included in a JCST evaluation report. Of these elements, 7 were considered essential by 70% or more of respondents, with 9 additional elements rated as either essential or recommended. A majority of respondents felt that the use of psychological and forensic instruments was important. A list of tests used is provided, and the implications for the development of standards and policy are discussed to provide practitioners with additional knowledge that will help to further the state of the discipline. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
刘洪 《湖南冶金职业技术学院学报》2004,(3)
心理健康不仅是时代发展对教育的必然要求,而且是实施素质教育的目标之一。为了培养高职学生良好的心理素质,针对高职学生心理素质存在的问题,就如何加强学生心理素质教育进行了探讨。 相似文献