全文获取类型
收费全文 | 1430篇 |
免费 | 28篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 225篇 |
金属工艺 | 6篇 |
机械仪表 | 27篇 |
建筑科学 | 93篇 |
矿业工程 | 4篇 |
能源动力 | 54篇 |
轻工业 | 147篇 |
水利工程 | 13篇 |
石油天然气 | 4篇 |
无线电 | 82篇 |
一般工业技术 | 145篇 |
冶金工业 | 437篇 |
原子能技术 | 5篇 |
自动化技术 | 209篇 |
出版年
2023年 | 8篇 |
2022年 | 29篇 |
2021年 | 32篇 |
2020年 | 25篇 |
2019年 | 24篇 |
2018年 | 18篇 |
2017年 | 19篇 |
2016年 | 32篇 |
2015年 | 31篇 |
2014年 | 37篇 |
2013年 | 72篇 |
2012年 | 56篇 |
2011年 | 84篇 |
2010年 | 64篇 |
2009年 | 67篇 |
2008年 | 69篇 |
2007年 | 60篇 |
2006年 | 63篇 |
2005年 | 35篇 |
2004年 | 37篇 |
2003年 | 30篇 |
2002年 | 44篇 |
2001年 | 28篇 |
2000年 | 15篇 |
1999年 | 31篇 |
1998年 | 17篇 |
1997年 | 12篇 |
1996年 | 18篇 |
1995年 | 24篇 |
1994年 | 25篇 |
1993年 | 29篇 |
1992年 | 24篇 |
1990年 | 23篇 |
1989年 | 13篇 |
1988年 | 19篇 |
1987年 | 22篇 |
1986年 | 15篇 |
1985年 | 24篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 10篇 |
1969年 | 6篇 |
排序方式: 共有1458条查询结果,搜索用时 0 毫秒
51.
Kennard Betsy D.; Clarke Greg N.; Weersing V. Robin; Asarnow Joan Rosenbaum; Shamseddeen Wael; Porta Giovanna; Berk Michele; Hughes Jennifer L.; Spirito Anthony; Emslie Graham J.; Keller Martin B.; Wagner Karen D.; Brent David A. 《Canadian Metallurgical Quarterly》2009,77(6):1033
In this report, we conducted a secondary analysis of the Treatment of SSRI-Resistant Depression in Adolescents (TORDIA) study to explore the impact of specific cognitive–behavioral therapy (CBT) treatment components on outcome. In TORDIA, 334 youths (ages 12 to 18 years) with major depressive disorder who had failed to respond to an adequate course of selective serotonin reuptake inhibitor (SSRI) medication were randomized to a medication switch (either to an alternative SSRI or venlafaxine) with or without 12 weeks of adjunctive CBT. Participants who had more than 9 CBT sessions were 2.5 times more likely to have adequate treatment response than those who had 9 or fewer sessions. CBT participants who received problem-solving and social skills treatment components, controlling for number of sessions and other confounding variables, were 2.3 and 2.6 times, respectively, more likely to have a positive response. These preliminary findings underscore the importance of receiving an adequate number of sessions to attain an adequate clinical response. Finally, social skills and problem solving may be active elements in CBT for adolescent depression and should be considered in treatment by those working with seriously depressed youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
We present a numerical formulation to compute optical parameters in a turbulent air flow. The basic numerical formulation is a large eddy simulation (LES) of the incompressible Navier-Stokes equations, which are approximated using a finite element method. From the time evolution of the flow parameters we describe how to compute statistics of the flow variables and, from them, the parameters that determine the quality of the visibility. The methodology is applied to estimate the optical quality around telescope enclosures. 相似文献
53.
Four of Rodolfa et al.’s (2005) competencies in professional psychology—relationship, self-reflection, assessment-case conceptualization, and intervention—are key for the psychodynamic psychotherapist. Relationship lies at the heart of what is understood to be curative about psychodynamic psychotherapy. Self-reflection implies a complex and highly developed process that includes but goes beyond Rodolfa et al.’s and Kaslow, Dunn, and Smith’s (2008) definitions. Competent assessment, diagnosis, and case conceptualization entails making inferences about unconscious processes by observing the client and also one’s own experience, and integrating these inferences with theory. Effective psychodynamic intervention is derived from what the psychotherapist has experienced, processed, and conceptualized about the relationship with the client and about the client’s internal object world. An extended vignette shows these competencies emerging in a psychotherapist-in-training, facilitated by an intense interaction with a supervisor. Although the supervisory and clinical tasks are different, the supervisor provides a relationship experience that models these same competencies for the supervisee and catalyzes their development in the supervisee. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
54.
Joan R. Casas 《Construction and Building Materials》2009,23(8):2964-2972
The paper presents the development of a model for the fatigue resistance of brick masonry under compression. The model takes into account the random nature of the fatigue strength phenomena and, as a consequence, proposes different model parameters as a function of the desired probability level. The model, based on a Weibull distribution, has been calibrated with the still limited experimental data on brick masonry under high cycle compression loading. Very good correlation is obtained. The results show that there is a clear trend of the experimental data to follow the Weibull distribution. It is also shown how the fatigue resistance of brick masonry is not only dependent on the magnitude of the stress cycles, but also on the magnitude of the minimum stress level. The paper also shows how the proposed model can be used in the reliability-based assessment of the fatigue performance of existing masonry arch bridges. Either the nominal probability of failure (reliability index) to fatigue or the remaining service life with a predefined probability level for an existing bridge can be predicted with the proposed method. 相似文献
55.
Davies W. Hobart; Satter Ellyn; Berlin Kristoffer S.; Sato Amy F.; Silverman Alan H.; Fischer Elizabeth A.; Arvedson Joan C.; Rudolph Colin D. 《Canadian Metallurgical Quarterly》2006,20(3):409
The feeding of young children is fundamentally a relational and multisystemic process. Successful treatment of clinically significant feeding problems involves careful assessment of the full range of influences on the feeding relationship and integrated treatment approaches. However, current diagnostic approaches to feeding disorders tend to be reductionistic, exclusively focused on the child as an individual, and overly concerned with exclusionary criteria. Criteria are proposed for "Feeding Disorder Between Parent and Child" that address these limitations and embrace the complexity of feeding problems. A multiaxial diagnosis that describes the child (including medical, developmental, and behavioral characteristics); the parent; the parent-child relationship; and the social and nutritional context of feeding will more accurately speak to treatment planning in this population. The proposed diagnostic criteria were developed and refined on the basis of the available literature and many years of treatment experience across the authors of this article. The proposed diagnosis will support the development and evaluation of treatment packages with components specifically targeted to issues of the child, parent, parent-child interaction, and the broader environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
Cole David A.; Nolen-Hoeksema Susan; Girgus Joan; Paul Gilda 《Canadian Metallurgical Quarterly》2006,115(1):40
In 2 longitudinal studies of negative life events and depressive symptoms in adolescents (N = 708) and in children (N = 508), latent trait-state-error structural equation models tested both the stress generation hypothesis and the stress exposure hypothesis. Results strongly suggested that self-reports of depressive symptoms reflect the influence of a perfectly stable trait factor as well as a less stable state factor. Support emerged for both the stress generation model and the stress exposure model. When the state depression factor was modeled as predicting stress, support for the stress generation model appeared to increase with age. When the trait depression factor was modeled as the predictor of stress, support for the stress generation model did not vary with the child's age. In both models, support for the stress exposure remained relatively constant across age. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
Tucker Joan S.; Ellickson Phyllis L.; Collins Rebecca L.; Klein David J. 《Canadian Metallurgical Quarterly》2006,20(4):363
This longitudinal study compared Grade 8 solitary cigarette smokers (n = 541), drinkers (n = 577), and marijuana users (n = 148) with adolescents who restricted their use of these substances to social settings (ns = 562, 1,426, and 388, respectively) on adolescent functioning and young adult outcomes. In Grade 8, solitary users held more positive beliefs about the consequences of substance use, earned poorer grades, engaged in more deviant behavior, and devoted less time to school and more time to social activities. By age 23, these solitary users had lower educational attainment, poorer self-rated health, and greater substance use problems. Results indicate the importance of better understanding and addressing the needs of this understudied group of high-risk youth. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
Joan Moss Ruth Beatty 《International Journal of Computer-Supported Collaborative Learning》2006,1(4):441-465
While it has been suggested that patterning activities support early algebra learning, it is widely acknowledged that the
shift from perceiving patterns to understanding algebraic functions—and correspondingly, from reporting empirical patterns
to providing explanations—is difficult. This paper reports on the collaborations of grade 4 students (n = 68) from three classrooms in diverse urban settings, connected through a knowledge-building environment (Knowledge Forum),
when solving mathematical generalizing problems as part of an early algebra research project. The purpose of this study was
to investigate the underlying principles of idea improvement and epistemic agency and the potential of knowledge building—as
supported by Knowledge Forum—to support student work. Our analyses of student-generated collaborative workspaces revealed
that students were able to find multiple rules for challenging problems and revise their own conjectures regarding those rules.
Furthermore, the discourse was sustained over 8 weeks and students were able to find similarities across problem types without
the support of teachers or researchers, suggesting that these grade-4 students had developed a disposition for evidence use
and justification that eludes much older students. 相似文献
59.
Miguel A. Rodriguez Joan E. Ricart Pablo Sanchez 《Creativity & Innovation Management》2002,11(3):135-146
Does the need for sustainable development hinder businesses’ ability to create value? Is a firm’s competitiveness negatively affected by considering that need? After quickly reviewing the main literature contributions on the relationship between business and society, and drawing from resource‐based view of the firm and sustainable development literature, this paper presents a proposal for a dynamic and sustainable view of the firm. It shows how considering the changes introduced into the competitive landscape by sustainable development influences the way in which companies develop their resources, capabilities and activities, fostering the persistence of competitive advantages based on knowledge and innovation. 相似文献
60.
Joan Peuteman Joan Peuteman Dirk Aeyels 《Mathematics of Control, Signals, and Systems (MCSS)》2002,15(3):202-228
Let be a time-varying vector field depending on t containing a regular and a slow time scale (α large). Assume there exist a k (τ)≥1 and a γ(τ) such that ∥x
τ(t, t
0, x
0)∥≤k(τ) e
−γ(τ)(t−t0)∥x
0∥, with x
τ(t, t
0, x
0) the solution of the parametrized system with initial state x
0 at t
0. We show that for α sufficiently large is exponentially stable when “on average”γ(τ) is positive. The use of this result is illustrated by means of two examples.
First, we extend the circle criterion. Second, exponential stability for a pendulum with a nonlinear slowly time-varying friction
attaining positive and negative values is discussed.
Date received: January 22, 2000. Date revised: April 14, 2001. 相似文献