全文获取类型
收费全文 | 1501篇 |
免费 | 73篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
综合类 | 2篇 |
化学工业 | 295篇 |
金属工艺 | 22篇 |
机械仪表 | 27篇 |
建筑科学 | 81篇 |
矿业工程 | 1篇 |
能源动力 | 46篇 |
轻工业 | 107篇 |
水利工程 | 15篇 |
石油天然气 | 2篇 |
无线电 | 85篇 |
一般工业技术 | 414篇 |
冶金工业 | 194篇 |
原子能技术 | 12篇 |
自动化技术 | 255篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 24篇 |
2021年 | 41篇 |
2020年 | 20篇 |
2019年 | 27篇 |
2018年 | 33篇 |
2017年 | 31篇 |
2016年 | 38篇 |
2015年 | 44篇 |
2014年 | 70篇 |
2013年 | 88篇 |
2012年 | 91篇 |
2011年 | 134篇 |
2010年 | 89篇 |
2009年 | 81篇 |
2008年 | 103篇 |
2007年 | 114篇 |
2006年 | 89篇 |
2005年 | 86篇 |
2004年 | 55篇 |
2003年 | 48篇 |
2002年 | 38篇 |
2001年 | 27篇 |
2000年 | 17篇 |
1999年 | 17篇 |
1998年 | 19篇 |
1997年 | 16篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1577条查询结果,搜索用时 15 毫秒
111.
Experiencing Nature: Embodying Animals in Immersive Virtual Environments Increases Inclusion of Nature in Self and Involvement With Nature 下载免费PDF全文
Sun Joo Ahn Joshua Bostick Elise Ogle Kristine L. Nowak Kara T. McGillicuddy Jeremy N. Bailenson 《Journal of Computer-Mediated Communication》2016,21(6):399-419
Immersive virtual environments (IVEs) produce simulations that mimic unmediated sensory experiences. 3 experiments (N = 228) tested how different modalities increase environmental involvement by allowing users to inhabit the body of animals in IVEs or watch the experience on video. Embodying sensory‐rich experiences of animals in IVEs led to greater feeling of embodiment, perception of being present in the virtual world, and interconnection between the self and nature compared to video. Heightened interconnection with nature elicited greater perceptions of imminence of the environmental risk and involvement with nature, which persisted for 1 week. Although the effect sizes were small to moderate, findings suggest that embodied experiences in IVEs may be an effective tool to promote involvement with environmental issues. 相似文献
112.
The importance of axial misalignment at polyethylene pipe butt fusion joints has been assessed by undertaking elevated temperature lifetime tests. Both medium and high density polyethylene pipes were fusion joined to give aligned and controlled misaligned butt joints. These were tested under either a constant or fluctuating internal pressure loading using conditions that induced failure by slow, stable crck growth. It was observed that the lifetime of a butt joined system depends upon both the internal pressure or pressure range applied and the level of misalignment at the butt fusion joint. Increasing either the internal pressure (range) or the misalignment reduced system performance. These two variables of misalignment and internal pressure (range) may be incorporated into a single parameter, the amplified axial stress (or stress range) at the butt joint. This amplified or butt joint axial stress (or stress range) may be derived by considering the additional bending stresses introduced at the butt joint by virtue of misalignment combined with the axial stress loading. 相似文献
113.
Voting in Multi-Agent Systems 总被引:1,自引:0,他引:1
114.
Floccia Caroline; Goslin Jeremy; Girard Frédérique; Konopczynski Gabrielle 《Canadian Metallurgical Quarterly》2006,32(5):1276
The processing costs involved in regional accent normalization were evaluated by measuring differences in lexical decision latencies for targets placed at the end of sentences with different French regional accents. Over a series of 6 experiments, the authors examined the time course of comprehension disruption by manipulating the duration and presentation conditions of accented speech. Taken together, the findings of these experiments indicate that regional accent normalization involves a short-term adjustment mechanism that develops as a certain amount of accented signal is available, resulting in a temporary perturbation in speech processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
115.
Emotional states might selectively modulate components of cognitive control. To test this hypothesis, the author randomly assigned 152 undergraduates (equal numbers of men and women) to watch short videos intended to induce emotional states (approach, neutral, or withdrawal). Each video was followed by a computerized 2-back working memory task (spatial or verbal, equated for difficulty and appearance). Spatial 2-back performance was enhanced by a withdrawal state and impaired by an approach state; the opposite pattern held for verbal performance. The double dissociation held more strongly for participants who made more errors than average across conditions. The results suggest that approach–withdrawal states can have selective influences on components of cognitive control, possibly on a hemispheric basis. They support and extend several frameworks for conceptualizing emotion–cognition interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
116.
Ship activity patterns depicted by the International Comprehensive Ocean-Atmosphere Data Set (ICOADS), the Automated Mutual-Assistance Vessel Rescue System (AMVER) data set, and their combination demonstrate different spatial and statistical sampling biases. These differences could significantly affect the accuracy of ship emissions inventories and atmospheric modeling. We demonstrate (using ICOADS) a method to improve global-proxy representativeness by trimming over-reporting vessels that mitigates sampling bias, augment the sample data set, and account for ship heterogeneity. Apparent underreporting to ICOADS and AMVER by ships near coastlines, perhaps engaged in coastwise (short sea) shipping especially in Europe, indicates that bottom-up regional inventories may be more representative locally. Primarily due to the long time series available publicly for ICOADS data, the improved ICOADS data set may be the most appropriate global ship traffic proxy identified to date to be used for a top-down approach. More generally, these three spatial proxies can be used together to perform uncertainty analyses of ship air-emissions impacts on a global scale (http://coast.cms.udel.edu/GlobalShipEmissions/). 相似文献
117.
Biesanz Jeremy C.; West Stephen G.; Millevoi Allison 《Canadian Metallurgical Quarterly》2007,92(1):119
Theory and research examining length of acquaintance and consensus among personality judgments have predominantly examined each dimension of personality separately. In L. J. Cronbach's (1955) terminology, this trait-centered approach combines consensus on elevation, differential elevation, and differential accuracy in personality judgments. The current article extends D. A. Kenny's (1991, 1994) weighted average model (WAM)--a theoretical model of the factors that influence agreement among personality judgments--to separate out two of Cronbach's components of consensus: stereotype accuracy and differential accuracy. Consistent with the predictions based on the WAM, as length of acquaintance increased, self-other agreement and consensus differential accuracy increased, stereotype accuracy decreased, and trait-level or raw profile correlations generally remained unchanged. Discussion focuses on the conditions under which a relationship between length of acquaintance and consensus and self-other agreement among personality evaluations emerges and how impressions change over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
118.
Marcus MS Shang L Li B Streifer JA Beck JD Perkins E Eriksson MA Hamers RJ 《Small (Weinheim an der Bergstrasse, Germany)》2007,3(9):1610-1617
Dielectrophoretic manipulation of nanoscale materials is typically performed in nonionic, highly insulating solvents. However, biomolecular recognition processes, such as DNA hybridization and protein binding, typically operate in highly conducting, aqueous saline solutions. Here, we report investigations of the manipulation and real-time detection of individual nanowires bridging microelectrode gaps in saline solutions. Measurements of the electrode impedance versus frequency show a crossover in behavior at a critical frequency that is dependent on the ionic strength. We demonstrate that by operating above this critical frequency, it is possible to use dielectrophoresis to manipulate nanowires across electrode gaps in saline solutions. By using electrical ground planes and nulling schemes to reduce the background currents, we further demonstrate the ability to electrically detect bridging and unbridging events of individual nanowires in saline solutions. The ability to both manipulate and detect bridging events with electrical signals provides a pathway toward automated assembly of nanoscale devices that incorporate biomolecular recognition elements. 相似文献
119.
Alexander B Rabovsky Andrei M Komarov Jeremy S Ivie Garry R Buettner 《Nutrition journal》2010,9(1):61
Multivitamin/multimineral complexes are the most common dietary supplements. Unlike minerals in foods that are incorporated in bioorganic structures, minerals in dietary supplements are typically in an inorganic form. These minerals can catalyze the generation of free radicals, thereby oxidizing antioxidants during digestion. Here we examine the ability of a matrix consisting of an amino acid and non-digestible oligosaccharide (AAOS) to blunt metal-catalyzed oxidations. Monitoring of ascorbate radical generated by copper shows that ascorbate is oxidized more slowly with the AAOS matrix than with copper sulfate. Measurement of the rate of oxidation of ascorbic acid and Trolox® by catalytic metals confirmed the ability of AAOS to slow these oxidations. Similar results were observed with iron-catalyzed formation of hydroxyl radicals. When compared to traditional forms of minerals used in supplements, we conclude that the oxidative loss of antioxidants in solution at physiological pH is much slower when AAOS is present. 相似文献
120.
Jeremy D. Jackson Anthony J. Yezzi Stefano Soatto 《International Journal of Computer Vision》2008,79(1):71-84
We propose a model of the shape, motion and appearance of a scene, seen through a sequence of images, that captures occlusions,
scene deformations, unconstrained viewpoint variations and changes in its radiance. This model is based on a collection of
overlapping layers that can move and deform, each supporting an intensity function that can change over time. We discuss the
generality and limitations of this model in relation to existing ones such as traditional optical flow or motion segmentation,
layers, deformable templates and deformotion. We then illustrate how this model can be used for inference of shape, motion,
deformation and appearance of the scene from a collection of images. The layering structure allows for automatic inpainting
of partially occluded regions. We illustrate the model on synthetic and real sequences where existing schemes fail, and show
how suitable choices of constants in the model yield existing schemes, from optical flow to motion segmentation and inpainting. 相似文献