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   234篇
  免费   5篇
  国内免费   1篇
化学工业   29篇
金属工艺   27篇
机械仪表   1篇
建筑科学   7篇
能源动力   1篇
轻工业   13篇
水利工程   5篇
无线电   13篇
一般工业技术   25篇
冶金工业   66篇
自动化技术   53篇
  2023年   1篇
  2022年   4篇
  2021年   4篇
  2020年   5篇
  2019年   3篇
  2018年   3篇
  2017年   4篇
  2016年   3篇
  2014年   8篇
  2013年   12篇
  2012年   6篇
  2011年   9篇
  2010年   7篇
  2009年   14篇
  2008年   8篇
  2007年   15篇
  2006年   19篇
  2005年   9篇
  2004年   11篇
  2003年   9篇
  2002年   9篇
  2001年   12篇
  2000年   6篇
  1999年   7篇
  1998年   6篇
  1997年   5篇
  1996年   10篇
  1995年   13篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1982年   2篇
排序方式: 共有240条查询结果,搜索用时 15 毫秒
1.
This study investigated the Stages of Change Readiness and Treatment Eagerness Scale (SOCRATES: W. R. Miller & J. S. Tonigan, 1996) in adolescents presenting for treatment of alcohol use disorder (AUD). The participants were 80 males and 43 females (mean age=16.8 years) who presented for AUD treatment (95.1% outpatient, 4.9% inpatient). Participants completed assessments at baseline and 1 year and provided information on alcohol use and related variables monthly between these 2 assessments. Principal-components and confirmatory factor analyses of the baseline SOCRATES identified 2 factors, Taking Steps and Recognition, which showed good internal consistency and concurrent and predictive evidence of validity. The results were interpreted as supporting the use of the SOCRATES with clinical samples of adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
This study examined organizational family-responsive policies, perceptions of the organization as family supportive, and supervisor support as issues that may be salient to the experience of conflict between paid employment (work) and family roles. Data were collected from 355 managerial personnel in New Zealand. Although work-family conflict and psychological strain were strongly linked, the availability of organizational policies had no significant association with levels of conflict or strain, whereas policy usage was related only to work-to-family interference and not to family-to-work interference. On the other hand, perceptions of the organization as family supportive and supervisor support for work-family balance displayed significant relationships with key variables, highlighting the importance of these variables for interventions designed to ameliorate the negative impact of work-family conflict on managerial well-being. Implications for the effective implementation of family-responsive interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
4.
Traditional models of bendable surfaces are based on the exact or approximate invariance to deformations that do not tear or stretch the shape, leaving intact an intrinsic geometry associated with it. These geometries are typically defined using either the shortest path length (geodesic distance), or properties of heat diffusion (diffusion distance) on the surface. Both measures are implicitly derived from the metric induced by the ambient Euclidean space. In this paper, we depart from this restrictive assumption by observing that a different choice of the metric results in a richer set of geometric invariants. We apply equi-affine geometry for analyzing arbitrary shapes with positive Gaussian curvature. The potential of the proposed framework is explored in a range of applications such as shape matching and retrieval, symmetry detection, and computation of Voroni tessellation. We show that in some shape analysis tasks, equi-affine-invariant intrinsic geometries often outperform their Euclidean-based counterparts. We further explore the potential of this metric in facial anthropometry of newborns. We show that intrinsic properties of this homogeneous group are better captured using the equi-affine metric.  相似文献   
5.
Redesigning Purdue's Online Writing Lab (OWL) presented the opportunity for collaboration among Writing Center and Professional Writing Program members. While the article briefly describes the OWL redesign process, the argument focuses on collaboration and presents a model for sustainable intraprogram collaboration. Following Hawhee, usability research is defined as “invention-in-the-middle,” which offers a model for understanding research process as part of the infrastructure of new media instruction as described by DeVoss, Cushman, and Grabill. This article offers four stakeholder perspectives on the process of participatory technology design: of writing center administrators, graduate students, technical writing practitioners, and writing program graduate faculty members. The model asserted by this article presents a dynamic understanding of expertise and of fluidity in the roles of participants. Collaborative usability research, seen as invention-in-the-middle, contributes both to long-term sustainability of technological artifacts as well as the discursive interactions among stakeholders whose work supports these artifacts.  相似文献   
6.
Nucleating agents increase the impact strength, tensile strength, and tensile elasticity modulus of semicrystalline polymers. Nucleating agents also decrease product cycle times, resulting in a cost savings per product unit. We have synthesized and tested 15 compounds as nucleactors for polypropylene. Of these, trinapthylidene sorbitol, tri-(4-methyl-1-naphthylidene)sorbitol, tri-(4-methoxy-1-naphthylidene) sorbitol, and dibenzylidene xylitol are efficient nucleators of polypropylene. Trinaphthylidene sorbitol (tns) has two major diastereomers: The “S” diastereomer yields a faster crystallization rate for polypropylene than does the commercial nucleator dibenzylidene sorbitol (Millad 3905). Crystallization rates are 208 and 88, respectively (t min?1 × 1000). The “R” diastereomer, however, is a poor nucleator and interferes with the nucleating activity of the “S” diastereomer. A 52/48 mixture of diastereomers does not nucleate polypropylene, even at twice the concentration. This is first time that the importance of stereochemistry has been demonstrated in the nucleating action. © 1994 John Wiley & Sons, Inc.  相似文献   
7.
Journal of Intelligent Manufacturing - In droplet-on-demand liquid metal jetting (DoD-LMJ) additive manufacturing, complex physical interactions govern the droplet characteristics, such as size,...  相似文献   
8.
Whole body vibration (WBV) was measured on eight surface haulage trucks in three size classes (35, 100, 150 ton haul capacities). Vibration was measured at the seat/operator interface in accordance with the ISO 2631-1 standard during 1 h of normal operation. Highest acceleration readings were observed in the z-axis (vertical). Estimated equivalent daily exposure values in the range of 0.44–0.82 ms?2 were observed using the frequency-weighted r.m.s method and 8.7–16.4 ms?1.75 using the vibration dose value method. Assessment was carried out using ISO 2631-1 and 2631-5. Operators of surface haulage trucks are regularly exposed to WBV levels that exceed safety limits as dictated by the ISO 2631-1 standard. However, according to ISO 2631-5 the probability of an adverse health effect remains low. These findings confirm an apparent disagreement between the two analysis methods.  相似文献   
9.
In this paper we discuss regularization of images that take their value in matrix Lie groups. We describe an image as a section in a principal bundle which is a fibre bundle where the fiber (the feature space) is a Lie group. Via the scalar product on the Lie algebra, we define a bi-invariant metric on the Lie-group manifold. Thus, the fiber becomes a Riemannian manifold with respect to this metric. The induced metric from the principal bundle to the image manifold is obtained by means of the bi-invariant metric. A functional over the space of sections, i.e., the image manifolds, is defined. The resulting equations of motion generate a flow which evolves the sections in the spatial-Lie-group manifold. We suggest two different approaches to treat this functional and the corresponding PDEs. In the first approach we derive a set of coupled PDEs for the local coordinates of the Lie-group manifold. In the second approach a coordinate-free framework is proposed where the PDE is defined directly with respect to the Lie-group elements. This is a parameterization-free method. The differences between these two methods are discussed. We exemplify this framework on the well-known orientation diffusion problem, namely, the unit-circle S 1 which is identified with the group of rotations in two dimensions, SO(2). Regularization of the group of rotations in 3D and 4D, SO(3) and SO(4), respectively, is demonstrated as well.
Nir SochenEmail:
  相似文献   
10.
This study investigated the impact of different modes of scaffolding on students who are learning science through a web-based collaborative inquiry project in authentic classroom settings and explored the interaction effects with students’ characteristics. The intervention study aimed to improve domain-specific knowledge and metacognitive awareness during online information problem solving (IPS) as part of an online inquiry project. Three experimental conditions (teacher-enhanced scaffolding, technology-enhanced scaffolding, and both forms of scaffolding) were compared with a control condition in a two-by-two factorial quasi-experimental design. Moreover, gender and prior knowledge were examined as two factors which may have a significant impact on Web-based learning. In a four-week field study in secondary science education, pretest-posttest differences were measured. In total 347 students from 18 secondary school classes were involved and the classes were randomly distributed over the 4 conditions. Our findings support the notion of multiple scaffolding as an approach to enhance both knowledge acquisition and metacognitive awareness with respect to IPS-processes and to meet a mix of students with different needs within the context of a web-based inquiry learning project.  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