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   920篇
  免费   26篇
  国内免费   7篇
电工技术   11篇
综合类   3篇
化学工业   179篇
金属工艺   57篇
机械仪表   10篇
建筑科学   10篇
能源动力   30篇
轻工业   42篇
水利工程   11篇
无线电   127篇
一般工业技术   208篇
冶金工业   76篇
原子能技术   6篇
自动化技术   183篇
  2024年   3篇
  2023年   13篇
  2022年   20篇
  2021年   23篇
  2020年   21篇
  2019年   19篇
  2018年   24篇
  2017年   26篇
  2016年   25篇
  2015年   19篇
  2014年   43篇
  2013年   71篇
  2012年   34篇
  2011年   39篇
  2010年   48篇
  2009年   44篇
  2008年   44篇
  2007年   31篇
  2006年   35篇
  2005年   19篇
  2004年   17篇
  2003年   24篇
  2002年   28篇
  2001年   21篇
  2000年   18篇
  1999年   20篇
  1998年   30篇
  1997年   21篇
  1996年   21篇
  1995年   15篇
  1994年   13篇
  1993年   5篇
  1992年   17篇
  1991年   14篇
  1990年   10篇
  1989年   13篇
  1988年   8篇
  1987年   11篇
  1986年   3篇
  1985年   10篇
  1984年   4篇
  1983年   3篇
  1982年   6篇
  1981年   2篇
  1980年   7篇
  1979年   3篇
  1977年   3篇
  1976年   2篇
  1970年   1篇
  1969年   1篇
排序方式: 共有953条查询结果,搜索用时 15 毫秒
21.
In a cloud computing paradigm, energy efficient allocation of different virtualized ICT resources (servers, storage disks, and networks, and the like) is a complex problem due to the presence of heterogeneous application (e.g., content delivery networks, MapReduce, web applications, and the like) workloads having contentious allocation requirements in terms of ICT resource capacities (e.g., network bandwidth, processing speed, response time, etc.). Several recent papers have tried to address the issue of improving energy efficiency in allocating cloud resources to applications with varying degree of success. However, to the best of our knowledge there is no published literature on this subject that clearly articulates the research problem and provides research taxonomy for succinct classification of existing techniques. Hence, the main aim of this paper is to identify open challenges associated with energy efficient resource allocation. In this regard, the study, first, outlines the problem and existing hardware and software-based techniques available for this purpose. Furthermore, available techniques already presented in the literature are summarized based on the energy-efficient research dimension taxonomy. The advantages and disadvantages of the existing techniques are comprehensively analyzed against the proposed research dimension taxonomy namely: resource adaption policy, objective function, allocation method, allocation operation, and interoperability.  相似文献   
22.
Multimedia Tools and Applications - Medical image watermarking is a challenging area of research. High bandwidth, secure transmission of patient’s data among hospitals and hiding capacity are...  相似文献   
23.
24.
Dynamic slicing is a promising trace based technique that helps programmers in the process of debugging. In order to debug a failed run, dynamic slicing requires the dynamic dependence graph (DDG) information for that particular run. The two major challenges involved in utilizing dynamic slicing as a debugging technique are the efficient computation of the DDG and the efficient computation of the dynamic slice, given the DDG. In this paper, we present an efficient debugger, which first computes the DDG efficiently while the program is executing; dynamic slicing is later performed efficiently on the computed DDG, on demand. To minimize program slowdown during the online computation of DDG, we make the design decision of not outputting the computed dependencies to a file, instead, storing them in memory in a specially allocated fixed size circular buffer. The size of the buffer limits the length of the execution history that can be stored. To maximize the execution history that can be maintained, we introduce optimizations to eliminate the storage of most of the generated dependencies, at the same time ensuring that those that are stored are sufficient to capture the bug. Experiments conducted on CPU‐intensive programs show that our optimizations are able to reduce the trace rate from 16 to 0.8 bytes per executed instruction. This enables us to store the dependence trace history for a window of 20 million executed instructions in a 16‐MB buffer. Our debugger is also very efficient, yielding slicing times of around a second, and only slowing down the execution of the program by a factor of 19 during the online tracing step. Using recently proposed architectural support for monitoring, we are also able to handle multithreaded programs running on multicore processors. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
25.
Nonaqueous polymer gel electrolytes containing ammonium triflate (NH4CF3SO3) and dimethylacetamide (DMA) with polymethylmethacrylate (PMMA) as the gelling polymer have been synthesized which show high value of conductivity (~ 10-2 S/cm) at 25°C. The conductivity of polymer gel electrolytes containing different concentrations of NH4CF3SO3 shows a small decrease with the addition of PMMA and this has been correlated with the variation of fluidity of these gel electrolytes. The small decrease in conductivity with PMMA addition shows that polymer plays the role of stiffener and this is supported by FTIR results which also indicates the absence of any active interaction between polymer and NH4CF3SO3 in these gel electrolytes.  相似文献   
26.
Single crystals of the lamellar compound, ZrSe3, were grown by chemical vapour transport technique using iodine as a transporting agent. The grown crystals were characterized with the help of energy dispersive analysis by X-ray (EDAX), which gave confirmation about the stoichiometry. The optical band gap measurement of as grown crystals was carried out with the help of optical absorption spectra in the range 700–1450 nm. The indirect as well as direct band gap of ZrSe3 were found to be 1.1 eV and 1.47 eV, respectively. The resistivity of the as grown crystals was measured using van der Pauw method. The Hall parameters of the grown crystals were determined at room temperature from Hall effect measurements. Electrical resistivity measurements were performed on this crystal in the temperature range 303–423 K. The crystals were found to exhibit semiconducting nature in this range. The activation energy and anisotropy measurements were carried out for this crystal. Pressure dependence of electrical resistance was studied using Bridgman opposed anvils set up up to 8 GPa. The semiconducting nature of ZrSe3 single crystal was inferred from the graph of resistance vs pressure. The results obtained are discussed in detail.  相似文献   
27.
We address the problem of reconstructing a surface from irregularly spaced sparse and noisy range data while concurrently identifying and preserving the significant discontinuities in depth. It is well known that, starting from either the probabilistic Markov random field model or the mechanical membrane or thin plate model for the surface, the solution of the reconstruction problem can be eventually reduced to the global minimization of a certain “energy” function. Requiring the preservation of depth discontinuities makes the energy function nonconvex and replete with multiple local minima. We present a new method for obtaining discontinuity-preserving reconstruction based on the numerical solution of an appropriate Ito vector stochastic differential equation (SDE). The reconstructed surface is found by following the sample path of the (stochastic) diffusion process that solves the SDE in question. Our central contribution is the demonstration of the efficacy of the stochastic differential equation technique for solving a vision problem. Through comparisions of the results of our method to those of the two well-known existingglobalminimization based reconstruction techniques, we show a significant improvement in the final reconstructions obtained.  相似文献   
28.
Due to the exponential growth of the Internet users and wireless devices, interests on home networks have been enormously increased in recent days. In digital home networks, home services including remote access and control to home appliances as well as services offered by service providers are alluring. However, the remote control services cause digital home networks to have various security threats. Hence, for digital home networks, robust security services, especially remote user authentication, should be considered. This paper presents a robust and efficient authentication scheme based on strong-password approach to provide secure remote access in digital home network environments. The proposed scheme uses lightweight computation modules including hashed one-time password and hash-chaining technique along with low-cost smart card technology. It aims to satisfy several security requirements including stolen smart card attack and forward secrecy with lost smart card as well as functional requirements including no verification table and no time synchronization. Comparing with the existing representative schemes, it can be validated that the proposed scheme is more robust authentication mechanism having better security properties. We have conducted formal verification of the proposed scheme.  相似文献   
29.
Application software for Intel's 8052AH-basic microcontroller can be developed in MCS basic-52, an enhanced version of basic, using the onchip basic interpreter. The paper explores the 8052AH-basic device and its language in comparison with the standard Microsoft basic and presents some software routines and other guidelines for programmers. Control-oriented applications, as opposed to conventional number-crunching applications, are emphasized. The paper also discusses how the resources of the Intellec development system can be used to facilitate the development of application software.  相似文献   
30.
The adulteration/substitution of meat has always been a concern for various reasons such as public health, religious factors, wholesomeness, and unhealthy competition in meat market. Consumer should be protected from these malicious practices of meat adulterations by quick, precise, and specific identification of meat animal species. Several analytical methodologies have been employed for meat speciation based on anatomical, histological, microscopic, organoleptic, chemical, electrophoretic, chromatographic, or immunological principles. However, by virtue of their inherent limitations, most of these techniques have been replaced by the recent DNA-based molecular techniques. In the last decades, several methods based on polymerase chain reaction have been proposed as useful means for identifying the species origin in meat and meat products, due to their high specificity and sensitivity, as well as rapid processing time and low cost. This review intends to provide an updated and extensive overview on the DNA-based methods for species identification in meat and meat products.  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