全文获取类型
收费全文 | 3423篇 |
免费 | 238篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 41篇 |
化学工业 | 868篇 |
金属工艺 | 119篇 |
机械仪表 | 106篇 |
建筑科学 | 83篇 |
矿业工程 | 16篇 |
能源动力 | 137篇 |
轻工业 | 552篇 |
水利工程 | 27篇 |
石油天然气 | 8篇 |
无线电 | 168篇 |
一般工业技术 | 750篇 |
冶金工业 | 144篇 |
原子能技术 | 48篇 |
自动化技术 | 596篇 |
出版年
2023年 | 40篇 |
2022年 | 35篇 |
2021年 | 94篇 |
2020年 | 84篇 |
2019年 | 107篇 |
2018年 | 168篇 |
2017年 | 156篇 |
2016年 | 157篇 |
2015年 | 143篇 |
2014年 | 192篇 |
2013年 | 403篇 |
2012年 | 203篇 |
2011年 | 254篇 |
2010年 | 252篇 |
2009年 | 186篇 |
2008年 | 120篇 |
2007年 | 97篇 |
2006年 | 60篇 |
2005年 | 16篇 |
2004年 | 31篇 |
2003年 | 28篇 |
2002年 | 42篇 |
2001年 | 32篇 |
2000年 | 39篇 |
1999年 | 24篇 |
1998年 | 32篇 |
1997年 | 34篇 |
1996年 | 26篇 |
1995年 | 29篇 |
1994年 | 22篇 |
1993年 | 31篇 |
1992年 | 23篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 24篇 |
1988年 | 13篇 |
1986年 | 10篇 |
1985年 | 23篇 |
1984年 | 29篇 |
1983年 | 31篇 |
1982年 | 23篇 |
1981年 | 39篇 |
1980年 | 29篇 |
1979年 | 27篇 |
1978年 | 25篇 |
1977年 | 28篇 |
1976年 | 35篇 |
1975年 | 25篇 |
1974年 | 18篇 |
1973年 | 23篇 |
排序方式: 共有3663条查询结果,搜索用时 156 毫秒
51.
The specifics of business intelligence systems compared to operational IS motivate the necessity to research the business intelligence systems acceptance determinants separately. The authors followed an exploratory approach in order to conceptualize a business intelligence acceptance model. Their findings show that in the Business Intelligence Systems context, there is a significant emphasis on organizational factors, such as result demonstrability, social influence, and facilitating conditions with sufficient resources that help build an adequate information culture all substantially influencing the effective acceptance of business intelligence systems. 相似文献
52.
In this article, the neural network approach is exploited for development of bias‐dependent small‐signal and noise models of a class of microwave field effect transistor (FETs) made in the same technology but differing in the gate width. The prior knowledge neural approach is applied. Introducing gate width at the input of proposed neural networks, as well as the S/noise parameters of a device that belongs to the same class as the modeled device representing the prior knowledge, leads to very accurate scattering and noise parameters' modeling, as exemplified by modeling of class of pseudomorphic high electron mobility transistor (pHEMT) devices. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013. 相似文献
53.
Knowing the estimation of a statistical process’s parameters for measured network traffic is very important as it can then be further used for the statistical analyses and modeling of network traffic in simulation tools. It is for this reason that different estimation methods are proposed that allow estimations of the statistical processes of network traffic. One of them is our own histograms comparison (EMHC) based method that can be used to estimate statistical data-length process parameters from measured packet traffic. The main part of EMHC method is Mapping Algorithm with Fragmentation Mimics (MAFM). 相似文献
54.
Andrew Morrison Geska Helena Andersson Robert Brečević Synne Skjulstad 《Digital Creativity》2013,24(1-2):3-20
The metaphor of plasma is taken up to present and discuss movement and engagement by participants in mixed reality installation arts. Two works involving full body video portraits exhibited through large plasma screens in a variety of public settings are covered. Machinic mediations of video realism are considered in terms of embodied interaction in which viewer-participants contribute to the ‘disquiet’ of gendered figuring. Processural, proximal and personal aspects of responsive engagement are discussed. This is extended to performativity that may lead us to critical reflection of our own actions and responses in mixed reality arts. 相似文献
55.
Gerti Daschiel Milovan Perić Jovan Jovanović Antonio Delgado 《Microfluidics and nanofluidics》2013,15(5):675-687
The sub-laminar drag effect of microgroove surfaces was studied numerically in a steady two-dimensional channel flow at subcritical Reynolds numbers. Considerations are restricted to grooves of a few viscous length scales in depth, which are assumed not to promote the laminar to turbulent transition process. It was found that the drag reduction effect is due to the layout of grooves with respect to the flow direction and contour geometry. Results of computations show that for grooves of curved contour placed normal to the flow direction, drag arising from viscous and pressure forces is modulated due to the functional dependence of forces on the surface area projected in the flow direction. Such a groove layout leads to a large skin-friction reduction, but a comparable increase in pressure drag results in sub-laminar drag if drag over flat surface is considered as a reference. For a curved groove contour, the drag reduction increases with increasing Reynolds number and reaches about 5 % at Reynolds numbers approaching critical. 相似文献
56.
Franjo Ivančić Zijiang Yang Malay K. Ganai Aarti Gupta Pranav Ashar 《Theoretical computer science》2008
This paper discusses our methodology for formal analysis and automatic verification of software programs. It is applicable to a large subset of the C programming language that includes pointer arithmetic and bounded recursion. We consider reachability properties, in particular whether certain assertions or basic blocks are reachable in the source code, or whether certain standard property violations can occur. We perform this analysis via a translation to a Boolean circuit representation based on modeling basic blocks. The program is then analyzed by a back-end SAT-based bounded model checker, where each unrolling is mapped to one step in a block-wise execution of the program. 相似文献
57.
Roman Frič 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(1):63-70
We deal with categorical aspects of the extensions of generalized probability measures. In particular, we study various domains
of fuzzy sets, describe the relationships between σ-fields of crisp sets and generated Łukasiewicz tribes of measurable functions, and mention some probabilistic aspects. D-posets and sequential continuity play an important role.
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-0071-06, Protocol for Scientific
and Technological Collaboration between the Republic of Italy and Slovak Republic, Project No. 15: Algebraic and Logical Systems
of Soft Computing, and VEGA 2/6088/26. 相似文献
58.
The analysis of statistical parameters of computer-generated therfial images by a line-scanning technique indicates an approach to efficient image transmission. 相似文献
59.
Gisler T Rüger H Egelhaaf SU Tschumi J Schurtenberger P Rička J 《Applied optics》1995,34(18):3546-3553
We present a quantitative experimental comparison of fiber-based, single- and few-mode dynamic light scattering with the classical pinhole-detection optics. The recently presented theory of mode-selective dynamic light scattering [Appl. Opt. 32, 2860 (1993)] predicts a collection efficiency and a signal-tobaseline ratio superior to that of a classical pinhole setup. These predictions are confirmed by our experiments. Using single-mode optical fibers with different cutoff wavelengths and commercially available mechanical components, we have constructed a mode-selective detection optics in a simple and compact dynamic light-scattering spectrometer that permits an optimal compromise between signal intensity and dynamical resolution. 相似文献
60.
The flow stress of polycrystals is controlled by the processes occurring in the grain interior as well as in the mantle, i.e. at the grain boundary and its immediate vicinity. The early stages of evolution of dislocation substructure in these two regions with strain in 316L stainless steel polycrystals have been studied at 293 K, 673 K and 1123 K representing the low temperature thermal, the intermediate temperature athermal and the high temperature thermal regimes respectively. Specimens with grain sizes of 4 and 12 m were employed to determine the effect of grain size.Transmission electron microscopy studies on deformed specimens show the different roles of grain boundary and grain interior in different temperature regimes. In the low temperature regime grain boundaries act as obstacles to moving dislocations and as such high density of dislocation is found in the grain boundary vicinity. In the intermediate temperature regime the dislocations which are easily spread into the grain interior rearrange to form cell walls. In the high temperature regime grain boundaries transform to the equilibrium state and do not contain any grain boundary dislocations, and the distribution of dislocations within grains is homogeneous at all strains. Significantly higher values of dislocation densities in the vicinity as well as in the grain interior were found in the finer grain size material in the whole strain region employed. 相似文献