全文获取类型
收费全文 | 4294篇 |
免费 | 165篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 284篇 |
综合类 | 15篇 |
化学工业 | 1373篇 |
金属工艺 | 117篇 |
机械仪表 | 132篇 |
建筑科学 | 120篇 |
矿业工程 | 5篇 |
能源动力 | 206篇 |
轻工业 | 393篇 |
水利工程 | 18篇 |
石油天然气 | 6篇 |
无线电 | 285篇 |
一般工业技术 | 901篇 |
冶金工业 | 102篇 |
原子能技术 | 128篇 |
自动化技术 | 394篇 |
出版年
2023年 | 32篇 |
2022年 | 50篇 |
2021年 | 125篇 |
2020年 | 59篇 |
2019年 | 73篇 |
2018年 | 84篇 |
2017年 | 65篇 |
2016年 | 111篇 |
2015年 | 83篇 |
2014年 | 125篇 |
2013年 | 246篇 |
2012年 | 251篇 |
2011年 | 286篇 |
2010年 | 241篇 |
2009年 | 261篇 |
2008年 | 282篇 |
2007年 | 215篇 |
2006年 | 210篇 |
2005年 | 139篇 |
2004年 | 145篇 |
2003年 | 164篇 |
2002年 | 145篇 |
2001年 | 73篇 |
2000年 | 77篇 |
1999年 | 62篇 |
1998年 | 71篇 |
1997年 | 58篇 |
1996年 | 59篇 |
1995年 | 58篇 |
1994年 | 51篇 |
1993年 | 55篇 |
1992年 | 53篇 |
1991年 | 51篇 |
1990年 | 32篇 |
1989年 | 46篇 |
1988年 | 14篇 |
1987年 | 35篇 |
1986年 | 21篇 |
1985年 | 38篇 |
1984年 | 21篇 |
1983年 | 31篇 |
1982年 | 31篇 |
1981年 | 28篇 |
1980年 | 16篇 |
1979年 | 22篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1973年 | 7篇 |
排序方式: 共有4479条查询结果,搜索用时 15 毫秒
111.
FENECIA: failure endurable nested-transaction based execution of composite Web services with incorporated state analysis 总被引:1,自引:0,他引:1
Neila Ben Lakhal Takashi Kobayashi Haruo Yokota 《The VLDB Journal The International Journal on Very Large Data Bases》2009,18(1):1-56
Interest in the Web services (WS) composition (WSC) paradigm is increasing tremendously. A real shift in distributed computing
history is expected to occur when the dream of implementing Service-Oriented Architecture (SOA) is realized. However, there
is a long way to go to achieve such an ambitious goal. In this paper, we support the idea that, when challenging the WSC issue,
the earlier that the inevitability of failures is recognized and proper failure-handling mechanisms are defined, from the
very early stage of the composite WS (CWS) specification, the greater are the chances of achieving a significant gain in dependability.
To formalize this vision, we present the FENECIA (Failure Endurable Nested-transaction based Execution of Composite Web services with Incorporated state Analysis) framework. Our framework approaches the WSC issue from different points of view to guarantee a high level of dependability.
In particular, it aims at being simultaneously a failure-handling-devoted CWS specification, execution, and quality of service
(QoS) assessment approach. In the first section of our framework, we focus on answering the need for a specification model
tailored for the WS architecture. To this end, we introduce WS-SAGAS, a new transaction model. WS-SAGAS introduces key concepts that are not part of the WS architecture pillars, namely, arbitrary nesting, state, vitality degree, and compensation, to specify failure-endurable CWS as a hierarchy of recursively nested transactions. In addition, to define the CWS execution
semantics, without suffering from the hindrance of an XML-based notation, we describe a textual notation that describes a
WSC in terms of definition rules, composability rules, and ordering rules, and we introduce graphical and formal notations. These rules provide the solid foundation needed to formulate the execution
semantics of a CWS in terms of execution correctness verification dependencies. To ensure dependable execution of the CWS, we present in the second section of FENECIA our architecture THROWS, in which the execution control of the resulting CWS is distributed among engines, discovered dynamically, that communicate
in a peer-to-peer fashion. A dependable execution is guaranteed in THROWS by keeping track of the execution progress of a
CWS and by enforcing forward and backward recovery. We concentrate in the third section of our approach on showing how the
failure consideration is trivial in acquiring more accurate CWS QoS estimations. We propose a model that assesses several
QoS properties of CWS, which are specified as WS-SAGAS transactions and executed in THROWS. We validate our proposal and show
its feasibility and broad applicability by describing an implemented prototype and a case study. 相似文献
112.
The nonlinear nonequilibrium properties of reacting network systems are studied by computer simulations. It is shown that
the fluctuation in the population of each chemical species obeys a log-normal distribution, not the normal Gaussian distribution.
The reaction rate shows power-law decay with activation cost (energy), not the Arrhenius-type exponential decay observed in
a linear nonequilibrium regime. These two characteristic features will explain the diversity, plasticity, and adaptivity observed
in complex biological reaction networks.
This work was presented in part at the 13th International Symposium on Artifical Life and Robotics, Oita, Japan, January 31–February
2, 2008 相似文献
113.
Isao Kobayashi Yoichi Murayama Takashi Kuroiwa Kunihiko Uemura Mitsutoshi Nakajima 《Microfluidics and nanofluidics》2009,7(1):107-119
This paper reports the production of monodisperse water-in-oil (W/O) emulsions using new microchannel emulsification (MCE)
devices, asymmetric straight-through MC arrays that were hydrophobically modified. The silicon asymmetric straight-through
MC arrays consisted of numerous pairs of microslots and circular microholes whose cross-sectional sizes were 10 μm. This paper
primarily focused on investigating the effect of the osmotic pressure of a dispersed phase (Πd) on MCE. This paper also investigated the effects of the type of continuous-phase oils and the dispersed-phase flux (J
d) on MCE. The dispersed phases were Milli-Q water and Milli-Q water solutions containing sodium chloride. The continuous phases
were decane (as control), hexane, medium chain triacylglyceride (MCT), and refined soybean oil (RSO) solutions containing
tetraglycerin monolaurate condensed ricinoleic acid ester (TGCR) as a surfactant. At Πd of exceeding threshold, highly uniform aqueous droplets with coefficients of variation of less than 3% were stably generated
via hydrophobic asymmetric straight-through MCs. Monodisperse W/O emulsions with average droplet diameters between 32 and
45 μm were produced using the alkane–oil and triglyceride–oil solutions as the continuous phase. This work also demonstrated
that the hydrophobic asymmetric straight-through MC array had remarkable ability to produce highly uniform aqueous droplets
at very high J
d of up to 1,200 L m−2 h−1. 相似文献
114.
Kuramochi K Suzuki K Yamazaki T Mitsuishi K Furuya K Hashimoto I Watanabe K 《Ultramicroscopy》2008,109(1):96-103
The structure and composition of the 1/4{110} twin boundary in alpha-Zn7Sb2O12 have been determined by using quantitative high-angle annular dark field scanning transmission electron microscopy (HAADF STEM) analysis. The noise in the experimental HAADF STEM images is reduced by using the maximum entropy method and average processing, and the parameters used in dynamical simulations are experimentally determined. From the analysis, it has been found that octahedral sites in the twin boundary slightly shift parallel to the [110] direction, and a reduction of the Sb concentration at the octahedral sites on the plane adjacent to the twin boundary was detected. The reduction was measured from three regions in the same twin boundary, and the Sb concentrations were 4 +/- 3, 8 +/- 3 and 19 +/-2 at% from 33 at%. 相似文献
115.
Masatsune Kato Takaaki Aoki Takashi Noji Yasuhiro Ono Yoji Koike Tomoyuki Hikita Yoshitami Saito 《Journal of Superconductivity》1994,7(1):37-38
We have investigated the relation between the crystal structure and superconductivity in La1.9Bi0.1CuO4+
, in which the phase separation observed in La2CuO4+
is suppressed. A phase diagram in theT– plane is given for La1.9Bi0.1CuO4+
with excess oxygen. For very small values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly at 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<<0.11. This is clear evidence thathigh-T
c
superconductivity also appears in the tetragonal phase. 相似文献
116.
Yuichi Ogawa Nobuyuki Inoue Jifang Wang Takashi Yamamoto Kunihiko Okano 《Journal of Fusion Energy》1995,14(4):353-359
Based on scientific databases adopted for designing ITER plasmas and on the advancement of fusion nuclear technology from the recent R&D program, a low wall-loading DEMO fusion reactor has been designed, where high priority has been given to the early and reliable realization of a tokamak fusion plasma over the cost performance. Since the major radius of this DEMO reactor is chosen to be 10 m, plasma ignition is achievable with a low fusion power of 0.8 GW and an operation period of 4–5 hours is available only with inductive current drive. The low ignition power makes it possible to adopt a first wall with an austenitic stainless steel, for which significant databases and operating experience exists, due to its use in the presence of neutron irradiation in fission reactors. In step with development of advanced materials, a step-wise increase of the fusion power seems to be feasible and realistic, because this DEMO reactor has the potential to produce a fusion power of 5 GW. 相似文献
117.
Takashi Tsuchida 《Electrical Engineering in Japan》2023,216(1):e23420
With the developments in power electronics equipment, the electromagnetic environment has become severe for electronic equipment. In the smart facility field, the stable operation of electronic devices is indispensable, and noise countermeasures must be improved. To suppress intrusive noise from cables, shielded cables are used in many cases. However, electromagnetic induction cannot be suppressed when the shield is grounded at one end, and when grounding both ends of the shield, current flows through the shield creating intrusive noise in the cable. That is, even if a shielded cable is used, a sufficient effect cannot be obtained. Therefore, as a countermeasure, this study prototypes and evaluates cables that combine double shielded cables with magnetic cores. Evaluations conducted using the copper pipe method, triaxial method, and impulse test confirm that the shielded performance improved by 10–30 dB compared with the conventional shielded cable. 相似文献
118.
Solution‐Processed Organic–Inorganic Perovskite Field‐Effect Transistors with High Hole Mobilities
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
119.
Molly S. Bazilchuk Takashi Sumigawa Takayuki Kitamura Zhiliang Zhang Helge Kristiansen Jianying He 《Advanced Engineering Materials》2018,20(7)
120.
Takashi Shimomura 《Dynamical Systems: An International Journal》2018,33(2):275-302
Downarowicz and Maass [7] proposed topological ranks for all homeomorphic Cantor minimal dynamical systems using properly ordered Bratteli diagrams. In this study, we adopt this definition to the case of the essentially minimal zero-dimensional systems. We consider the cases in which topological ranks are 2 and unique minimal sets are fixed points. Akin and Kolyada [2], had shown that if the unique minimal set of an essentially minimal system is a fixed point, then the system must be proximal. The finite topological rank implies expansiveness; furthermore, in the case of proximal Cantor systems with topological rank 2, the expansiveness is always from the lowest degree. Rank 2 proximal Cantor systems are residually scrambled. We present a necessary and sufficient condition for the unique ergodicity of these systems. In addition, we show that the number of ergodic measures of the systems that are topologically mixing can be 1 and 2. Moreover, we present examples that are topologically weakly mixing, not topologically mixing, and uniquely ergodic. Finally, we show that the number of ergodic measures of the systems that are not weakly mixing can be 1 and 2. 相似文献