全文获取类型
收费全文 | 3246篇 |
免费 | 199篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 56篇 |
综合类 | 14篇 |
化学工业 | 703篇 |
金属工艺 | 58篇 |
机械仪表 | 66篇 |
建筑科学 | 183篇 |
矿业工程 | 4篇 |
能源动力 | 95篇 |
轻工业 | 316篇 |
水利工程 | 30篇 |
石油天然气 | 22篇 |
无线电 | 258篇 |
一般工业技术 | 568篇 |
冶金工业 | 416篇 |
原子能技术 | 23篇 |
自动化技术 | 634篇 |
出版年
2023年 | 52篇 |
2022年 | 78篇 |
2021年 | 112篇 |
2020年 | 59篇 |
2019年 | 64篇 |
2018年 | 75篇 |
2017年 | 77篇 |
2016年 | 120篇 |
2015年 | 114篇 |
2014年 | 121篇 |
2013年 | 192篇 |
2012年 | 169篇 |
2011年 | 224篇 |
2010年 | 205篇 |
2009年 | 152篇 |
2008年 | 159篇 |
2007年 | 138篇 |
2006年 | 142篇 |
2005年 | 115篇 |
2004年 | 95篇 |
2003年 | 75篇 |
2002年 | 74篇 |
2001年 | 66篇 |
2000年 | 51篇 |
1999年 | 63篇 |
1998年 | 113篇 |
1997年 | 71篇 |
1996年 | 52篇 |
1995年 | 46篇 |
1994年 | 27篇 |
1993年 | 38篇 |
1992年 | 17篇 |
1991年 | 22篇 |
1990年 | 16篇 |
1989年 | 26篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 14篇 |
1985年 | 22篇 |
1984年 | 12篇 |
1983年 | 20篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1977年 | 6篇 |
1976年 | 21篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1968年 | 7篇 |
排序方式: 共有3446条查询结果,搜索用时 15 毫秒
51.
Hormones and many other neurotransmitters, growth factors, odorant molecules, and light all present stimuli for a class of membrane-anchored receptors called G protein-coupled receptors (GPCRs). The GPCRs are the largest family of cell-surface receptors involved in signal transduction. About 1% of all known genes of Drosophila and more than 5% of the genes of Caenorhabditis elegans encode GPCRs. In addition, more than 50% of current therapeutic agents on the market target these receptors. When the enormous biological and pharmaceutical importance of these receptors is considered, it is surprising how little is known about the mechanism with which these receptors recognize their natural ligands. In this review we present a structural approach, utilizing techniques of high-resolution NMR spectroscopy, to address the question of whether peptides from the neuropeptide Y family of neurohormones are recognized directly from solution or from the membrane-bound state. In our studies we discovered that the structures of the membrane-bound species are better correlated to the pharmacological properties of these peptides than the solution structures are. These findings are supported by the observation that many biophysical properties of these peptides seem to be optimized for membrane binding. We finally present a scenario of possible events during receptor recognition. 相似文献
52.
Jet loop reactors are used as apparatus to facilitate chemical or biological reactions. This type of apparatus is characterized by an internal circulation flow, essentially driven by the injection of liquid. The nozzle can also be used to inject and disperse gas. The internal fluid dynamics and thus the reactor behavior is significantly determined by the introduced momentum and by the internal gas distribution. To describe the mutual influence of a gas-consuming reaction and the internal fluid dynamics, a simplified model based on a momentum balance and a material balance was used. From the exemplary calculations, a critical range for non-selective reactions and for fluid dynamic stability is given. 相似文献
53.
Chaudry Oliver Friedberger Andreas Grimm Alexandra Uder Michael Nagel Armin Michael Kemmler Wolfgang Engelke Klaus 《Magma (New York, N.Y.)》2021,34(3):367-376
Magnetic Resonance Materials in Physics, Biology and Medicine - To develop a precise semi-automated segmentation of the fascia lata (FL) of the thigh to quantify IMAT volume in T1w MR images and... 相似文献
54.
55.
56.
Henning Zimmer Fabrice Rousselle Wenzel Jakob Oliver Wang David Adler Wojciech Jarosz Olga Sorkine‐Hornung Alexander Sorkine‐Hornung 《Computer Graphics Forum》2015,34(4):131-142
Renderings of animation sequences with physics‐based Monte Carlo light transport simulations are exceedingly costly to generate frame‐by‐frame, yet much of this computation is highly redundant due to the strong coherence in space, time and among samples. A promising approach pursued in prior work entails subsampling the sequence in space, time, and number of samples, followed by image‐based spatio‐temporal upsampling and denoising. These methods can provide significant performance gains, though major issues remain: firstly, in a multiple scattering simulation, the final pixel color is the composite of many different light transport phenomena, and this conflicting information causes artifacts in image‐based methods. Secondly, motion vectors are needed to establish correspondence between the pixels in different frames, but it is unclear how to obtain them for most kinds of light paths (e.g. an object seen through a curved glass panel). To reduce these ambiguities, we propose a general decomposition framework, where the final pixel color is separated into components corresponding to disjoint subsets of the space of light paths. Each component is accompanied by motion vectors and other auxiliary features such as reflectance and surface normals. The motion vectors of specular paths are computed using a temporal extension of manifold exploration and the remaining components use a specialized variant of optical flow. Our experiments show that this decomposition leads to significant improvements in three image‐based applications: denoising, spatial upsampling, and temporal interpolation. 相似文献
57.
58.
59.
60.
Oliver Bimber Daisuke Iwai Gordon Wetzstein Anselm Grundhöfer 《Computer Graphics Forum》2008,27(8):2219-2245
This article focuses on real‐time image correction techniques that enable projector‐camera systems to display images onto screens that are not optimized for projections, such as geometrically complex, coloured and textured surfaces. It reviews hardware‐accelerated methods like pixel‐precise geometric warping, radiometric compensation, multi‐focal projection and the correction of general light modulation effects. Online and offline calibration as well as invisible coding methods are explained. Novel attempts in super‐resolution, high‐dynamic range and high‐speed projection are discussed. These techniques open a variety of new applications for projection displays. Some of them will also be presented in this report. 相似文献