首页 | 官方网站   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   1173篇
  免费   82篇
  国内免费   1篇
工业技术   1256篇
  2024年   1篇
  2023年   21篇
  2022年   33篇
  2021年   51篇
  2020年   43篇
  2019年   34篇
  2018年   46篇
  2017年   47篇
  2016年   56篇
  2015年   41篇
  2014年   71篇
  2013年   78篇
  2012年   91篇
  2011年   119篇
  2010年   72篇
  2009年   61篇
  2008年   62篇
  2007年   62篇
  2006年   45篇
  2005年   37篇
  2004年   25篇
  2003年   22篇
  2002年   15篇
  2001年   6篇
  2000年   13篇
  1999年   13篇
  1998年   20篇
  1997年   11篇
  1996年   12篇
  1995年   5篇
  1994年   4篇
  1993年   1篇
  1992年   4篇
  1991年   3篇
  1990年   1篇
  1989年   3篇
  1988年   4篇
  1987年   2篇
  1986年   5篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   6篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有1256条查询结果,搜索用时 15 毫秒
101.
Malicious software and other attacks are a major concern in the computing ecosystem and there is a need to go beyond the answers based on untrusted software. Trusted and secure computing can add a new hardware dimension to software protection. Several secure computing hardware architectures using memory encryption and memory integrity checkers have been proposed during the past few years to provide applications with a tamper resistant environment. Some solutions, such as HIDE, have also been proposed to solve the problem of information leakage on the address bus. We propose the CRYPTOPAGE architecture which implements memory encryption, memory integrity protection checking and information leakage protection together with a low performance penalty (3% slowdown on average) by combining the Counter Mode of operation, local authentication values and MERKLE trees. It has also several other security features such as attestation, secure storage for applications and program identification. We present some applications of the CRYPTOPAGE architecture in the computer virology field as a proof of concept of improving security in presence of viruses compared to software only solutions.  相似文献   
102.
103.
104.
105.
Arsenic sorption onto iron oxide spinels such as magnetite may contribute to arsenic immobilization at redox fronts in soils, sediments, and aquifers, as well as in putative remediation and water treatment technologies. We have investigated As(V) speciation resulting from different sorption processes on magnetite nanoparticles, including both adsorption and precipitation, using X-ray absorption fine structure (XAFS) spectroscopy and transmission electron microscopy (TEM). XAFS results suggest that AsO(4) tetrahedra form predominantly inner-sphere bidentate corner-sharing ((2)C) complexes and outer-sphere complexes on magnetite in the adsorption experiments. In the precipitation experiments, an increasing fraction of AsO(4) tetrahedra appears to be incorporated in clusters having a magnetite-like local structure with increasing As loading, the remaining fraction of As being adsorbed at the surface of magnetite particles. In the sample with the highest As loading (15.7 μmol/m(2)) XAFS data indicate that As(V) is fully incorporated in such clusters. Such processes help to explain the significantly higher arsenic uptake in precipitation samples compared to those generated in adsorption experiments. In addition, for the precipitation samples, TEM observations indicate the formation of amorphous coatings and small (~3 nm) nanoparticles associated with larger (~20-40 nm) magnetite nanoparticles, which are absent in the adsorption samples. These results suggest that As(V) could form complexes at the surfaces of the small nanoparticles and could be progressively incorporated in their structure with increasing As loading. These results provide some of the fundamental knowledge about As(V)-magnetite interactions that is essential for developing effective water treatment technologies for arsenic.  相似文献   
106.
The present paper aims to demonstrate the interest of fuzzy inference systems in system modeling when human interaction is important. It discusses the originality of FIS and their capability to integrate expertise and rule learning from data into a single framework, analyzing their place relatively to concurrent approaches. An open source software implementation is presented, with a focus on the useful features for modeling. Two real world case studies are presented to illustrate the approach and the software utility.  相似文献   
107.
Starting from a commercial slurry of high purity α-Al2O3, freeze-dried powders, cast, filter-pressed or cold isostatically pressed samples were produced. Resulting powders or green bodies showing different particles packing were densified by spark plasma sintering (SPS) to obtain transparent polycrystalline α-Al2O3. Microstructure and real in-line transmittance (RIT) after SPS were dependent on the particles packing quality. Avoiding large agglomerates, narrowing the pore size distribution, reducing the most-frequent pore size (Dmode) and avoiding macroscopic heterogeneities within the green bodies enabled high RIT values to be achieved in the visible and near-infrared spectrum. However, a limit was achieved in the preparation of green bodies for which reducing the Dmode had no more influence on the optical behaviour of samples sintered by SPS. Finally, pure α-Al2O3 samples presenting a high RIT640 nm value of 53% were produced from all the green bodies obtained by the following techniques: filter-pressing, slip casting and cold isostatic pressing.  相似文献   
108.
In this paper, a novel statistical generative model to describe a face is presented, and is applied to the face authentication task. Classical generative models used so far in face recognition, such as Gaussian Mixture Models (GMMs) and Hidden Markov Models (HMMs) for instance, are making strong assumptions on the observations derived from a face image. Indeed, such models usually assume that local observations are independent, which is obviously not the case in a face. The presented model hence proposes to encode relationships between salient facial features by using a static Bayesian Network. Since robustness against imprecisely located faces is of great concern in a real-world scenario, authentication results are presented using automatically localised faces. Experiments conducted on the XM2VTS and the BANCA databases showed that the proposed approach is suitable for this task, since it reaches state-of-the-art results. We compare our model to baseline appearance-based systems (Eigenfaces and Fisherfaces) but also to classical generative models, namely GMM, HMM and pseudo-2DHMM.  相似文献   
109.
The Cauliflower Mosaic Virus “35S promotor” (p35S) and the Agrobacterium “Nopaline Synthase” terminator (tNOS) are the most represented generic recombinant elements in commercial genetically modified crops to date. A set of four new SYBR®Green qPCR methods targeting the “p35S” and “tNOS” core elements have been developed. These qPCR methods generate short amplicons of 147 and 75 bp for the “p35S” element and 172 and 69 bp for the “tNOS” element. Single target plasmids containing these amplicons were constructed and allow determining the nominal melting temperature (T m value) of each amplicon. The four methods are specific for their respective targets, and moreover, three of them are highly sensitive (up to 1–2 copies detectable) at a PCR efficiency ranging between 95 and 100%. The latter methods can detect their respective targets at 0.1% (w/w) gDNA levels and are suitable for detecting low levels of genetically modified materials containing the “p35S” and/or “tNOS” elements.  相似文献   
110.
We report here on an original “glass-PDMS-glass” electrochemiluminescence optofluidic device that integrates 32 electrodes on a large surface. This organic electrically powered light source has been integrated on chip using an alternative process based on a photopatternable silicone resist. Under a continuous flow rate, this device allows electrogenerated chemiluminescence for several minutes which would be very useful for future μTAS systems.  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-23

京公网安备 11010802026262号