全文获取类型
收费全文 | 268篇 |
免费 | 24篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 46篇 |
金属工艺 | 11篇 |
机械仪表 | 3篇 |
建筑科学 | 4篇 |
能源动力 | 6篇 |
轻工业 | 12篇 |
无线电 | 23篇 |
一般工业技术 | 50篇 |
冶金工业 | 58篇 |
原子能技术 | 1篇 |
自动化技术 | 73篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 19篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 20篇 |
2012年 | 9篇 |
2011年 | 22篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 13篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 21篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
排序方式: 共有292条查询结果,搜索用时 15 毫秒
1.
Changmo Kim Izhar Livne‐Bar Karsten Gronert Jeremy M. Sivak 《Molecular nutrition & food research》2020,64(4)
Lipoxins (LXs) are autacoids, specialized proresolving lipid mediators (SPMs) acting locally in a paracrine or autocrine fashion. They belong to a complex superfamily of dietary small polyunsaturated fatty acid (PUFA)–metabolites, which direct potent cellular responses to resolve inflammation and restore tissue homeostasis. Together, these SPM activities have been intensely studied in systemic inflammation and acute injury or infection, but less is known about LX signaling and activities in the central nervous system. LXs are derived from arachidonic acid, an omega‐6 PUFA. In addition to well‐established roles in systemic inflammation resolution, they have increasingly become implicated in regulating neuroinflammatory and neurodegenerative processes. In particular, chronic inflammation plays a central role in Alzheimer's disease (AD) etiology, and dysregulated LX production and activities have been reported in a variety of AD rodent models and clinical tissue samples, yet with complex and sometimes conflicting results. In addition, reduced LX production following retinal injury has been reported recently by the authors, and an intriguing direct neuronal activity promoting survival and homeostasis in retinal and cortical neurons is demonstrated. Here, the authors review and clarify this growing literature and suggest new research directions to further elaborate the role of lipoxins in neurodegeneration. 相似文献
2.
3.
Tauber D. Nagar R. Livne A. Eisenstein G. Koren U. Raybon G. 《Photonics Technology Letters, IEEE》1992,4(3):238-240
The authors report on the noise characteristics of InGaAs/InGaAsP multiple-quantum-well optical amplifiers operating near 1.5 μm. A noise figure of 4.4 dB is reported, verifying the predicted low-noise properties of quantum-well amplifiers 相似文献
4.
5.
This work utilizes proteoliposomes reconstituted with renal Na(+)-K(+)-ATPase to study effects of electrical potential (40-80 mV) on activation of pump-mediated fluxes of Na+ or Rb+ (K+) ions and on inhibitory effects of Rb+ ions or organic cations. The latter include guanidinium derivatives that are competitive Na(+)-like antagonists (David, P., Mayan, H., Cohen, H., Tal, D. M., and Karlish, S.J.D. (1992) J. Biol. Chem. 267, 1141-1149). Cytoplasmic side-positive diffusion potentials significantly decreased the K0.5 of Na+ at the cytoplasmic surface for activation of ATP-dependent Na(+)-K+ exchange but did not affect the inhibitory potency of Rb+ (K+) or any Na(+)-like antagonist. Diffusion potentials did not affect activation of Rb(+)-Rb+ exchange by Rb+ ions at the cytoplasmic surface and had only a minor effect on Rb+ activation at the extracellular surface. Previously, we proposed that the cation binding domain consists of two negatively charged sites, to which two K+ or two Na+ ions bind, and one neutral site for the third Na+ (Glynn, I. M., and Karlish, S.J.D. (1990) Annu. Rev. Biochem. 59, 171-205). The present experiments suggest that binding of a Na+ ion in the neutral site at the cytoplasmic surface is sensitive to voltage. By contrast, binding of Rb+ ions at the extracellular surface of renal pumps appears to be only weakly or insignificantly affected by voltage. Inferences on the identity of the charge-carrying steps, based on experiments using proteoliposomes, are discussed in relation to recent evidence that dissociation of Na+ or association of K+ ions, at the extracellular surface, represent the major charge-carrying steps. 相似文献
6.
Micha Livne Leonid Sigal Nikolaus F. Troje David J. Fleet 《Computer Vision and Image Understanding》2012,116(5):648-660
It is well known that biological motion conveys a wealth of socially meaningful information. From even a brief exposure, biological motion cues enable the recognition of familiar people, and the inference of attributes such as gender, age, mental state, actions and intentions. In this paper we show that from the output of a video-based 3D human tracking algorithm we can infer physical attributes (e.g., gender and weight) and aspects of mental state (e.g., happiness or sadness). In particular, with 3D articulated tracking we avoid the need for view-based models, specific camera viewpoints, and constrained domains. The task is useful for man–machine communication, and it provides a natural benchmark for evaluating the performance of 3D pose tracking methods (vs. conventional Euclidean joint error metrics). We show results on a large corpus of motion capture data and on the output of a simple 3D pose tracker applied to videos of people walking. 相似文献
7.
Hadar Averbuch‐Elor Yunhai Wang Yiming Qian Minglun Gong Johannes Kopf Hao Zhang Daniel Cohen‐Or 《Computer Graphics Forum》2015,34(2):131-142
We present a distillation algorithm which operates on a large, unstructured, and noisy collection of internet images returned from an online object query. We introduce the notion of a distilled set, which is a clean, coherent, and structured subset of inlier images. In addition, the object of interest is properly segmented out throughout the distilled set. Our approach is unsupervised, built on a novel clustering scheme, and solves the distillation and object segmentation problems simultaneously. In essence, instead of distilling the collection of images, we distill a collection of loosely cutout foreground “shapes”, which may or may not contain the queried object. Our key observation, which motivated our clustering scheme, is that outlier shapes are expected to be random in nature, whereas, inlier shapes, which do tightly enclose the object of interest, tend to be well supported by similar shapes captured in similar views. We analyze the commonalities among candidate foreground segments, without aiming to analyze their semantics, but simply by clustering similar shapes and considering only the most significant clusters representing non‐trivial shapes. We show that when tuned conservatively, our distillation algorithm is able to extract a near perfect subset of true inliers. Furthermore, we show that our technique scales well in the sense that the precision rate remains high, as the collection grows. We demonstrate the utility of our distillation results with a number of interesting graphics applications. 相似文献
8.
With the proliferation of macroergonomic field research, it is time to carefully examine how such research should be managed and implemented. We argue that the importance of attending to high-quality implementation of field research is equal to that of methodological rigor. One way to systematically manage the implementation process is to adopt a change management framework, wherein the research project is conceptualized as an instance of organization-level change. Consequently, principles for successful organization-level change from the literature on change management can be used to guide successful field research implementation. This paper briefly reviews that literature, deriving 30 principles of successful change management, covering topics such as political awareness, assembling the change team, generating buy-in, and management support. For each principle, corresponding suggestions for macroergonomic field research practice are presented. We urge other researchers to further develop and adopt frameworks that guide the implementation of field research. 相似文献
9.
10.
J Ellert-Zygad?owska D Radowska M Dubicka H Trocha M Or?owski J Magiera 《Canadian Metallurgical Quarterly》1996,41(1):62-68
We biologically assessed functions of several reconstituted surfactants with the same minimum surface tension (2-3 mN/m) as "complete" porcine pulmonary surfactant (natural surfactant) but with longer surface adsorption times. Administration of natural surfactant (adsorption time 0.29 s) into the lungs of surfactant-deficient immature rabbits brought a tidal volume of 16.1 +/- 4.4 (SD) ml/kg during mechanical ventilation with 40 breaths/min and 20 cmH2O insufflation pressure. In static pressure-volume recordings, these animals showed a lung volume of 62.4 +/- 9.7 ml/kg at 30 cmH2O airway pressure and maintained 55% of this volume when the pressure decreased to 5 cmH2O. With two reconstituted surfactants consisting of synthetic lipids or isolated lipids from porcine lungs plus surfactant-associated hydrophobic proteins (adsorption times 0.57 and 0.78 s, respectively), tidal volumes were < 38% of that with natural surfactant (P < 0.05), but static pressure-volume recordings were not different. Care is therefore needed in estimating the in vivo function of surfactant preparations from minimum surface tension or static pressure-volume measurements. 相似文献