全文获取类型
收费全文 | 2919篇 |
免费 | 84篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 152篇 |
综合类 | 4篇 |
化学工业 | 854篇 |
金属工艺 | 94篇 |
机械仪表 | 68篇 |
建筑科学 | 52篇 |
矿业工程 | 3篇 |
能源动力 | 118篇 |
轻工业 | 283篇 |
水利工程 | 12篇 |
石油天然气 | 4篇 |
无线电 | 165篇 |
一般工业技术 | 620篇 |
冶金工业 | 265篇 |
原子能技术 | 87篇 |
自动化技术 | 230篇 |
出版年
2023年 | 11篇 |
2022年 | 39篇 |
2021年 | 51篇 |
2020年 | 33篇 |
2019年 | 48篇 |
2018年 | 48篇 |
2017年 | 43篇 |
2016年 | 57篇 |
2015年 | 51篇 |
2014年 | 77篇 |
2013年 | 152篇 |
2012年 | 125篇 |
2011年 | 159篇 |
2010年 | 146篇 |
2009年 | 152篇 |
2008年 | 151篇 |
2007年 | 141篇 |
2006年 | 127篇 |
2005年 | 105篇 |
2004年 | 101篇 |
2003年 | 85篇 |
2002年 | 88篇 |
2001年 | 61篇 |
2000年 | 60篇 |
1999年 | 60篇 |
1998年 | 152篇 |
1997年 | 76篇 |
1996年 | 84篇 |
1995年 | 50篇 |
1994年 | 43篇 |
1993年 | 39篇 |
1992年 | 34篇 |
1991年 | 38篇 |
1990年 | 21篇 |
1989年 | 24篇 |
1988年 | 15篇 |
1987年 | 26篇 |
1986年 | 23篇 |
1985年 | 19篇 |
1984年 | 23篇 |
1983年 | 16篇 |
1982年 | 27篇 |
1981年 | 19篇 |
1980年 | 20篇 |
1979年 | 19篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 15篇 |
1974年 | 6篇 |
1910年 | 6篇 |
排序方式: 共有3011条查询结果,搜索用时 31 毫秒
101.
In [N. Alon, M. Feldman, A.D. Procaccia, M. Tennenholtz, A note on competitive diffusion through social networks, Inform. Process. Lett. 110 (2010) 221–225], the authors introduced a game-theoretic model of diffusion process through a network. They showed a relation between the diameter of a given network and existence of pure Nash equilibria in the game. Theorem 1 of their paper says that a pure Nash equilibrium exists if the diameter is at most two. However, we have an example which does not admit a pure Nash equilibrium even if the diameter is two. Hence we correct the statement of Theorem 1 of their paper. 相似文献
102.
For a large volume air cleanup system in nuclear fusion facility honeycomb type oxidizing catalyst offers more useful advantage in terms of their low pressure drop than the conventional particle packed bed. Scaling up examination of 35 times large volume Pd catalyst deposit on metal honeycomb Al–Cr-steel alloy had been performed comparing with fundamental small size honeycomb. The catalyst was heated up to over 400 °C with stepwise by combined the inner and external heaters under various flow rate of processing gas containing various concentrations of hydrogen and methane. Then oxidizing reaction rates and the catalytic activation energies were evaluated and thermal property of catalyst bed was estimated considering exothermic oxidizing reaction in the process gas. As a result it was revealed that the scaling up honeycomb catalyst bed would be practically useful for the air cleanup system. 相似文献
103.
Toshiaki Kikuma Tadao Ishikawa Masahiro Takasaki Hiroshi Mochikawa Atsuhiko Kuzumaki Kazuya Kodani Takeru Murao 《Electrical Engineering in Japan》2015,192(3):54-64
The recent years have seen an increasing trend in the cumulative installed capacity of distributed generators. As a result, voltage management may become difficult in existing power distribution systems in the future. A STATCOM (STAtic synchronous COMpensator) is a promising option for solving this problem because it can control reactive power rapidly and continuously. For a distribution system, STATCOM needs to be pole‐mounted to realize its low cost. However, a transformer for a STATCOM is large and heavy, and hence it is difficult to install a STATCOM on a distribution pole. We adopt a transformerless STATCOM to reduce STATCOM size and use SiC devices with low‐loss performance to obtain a more compact and efficient STATCOM. There are a large number of circuits available for a STATCOM, and there has been considerable research on performance comparisons among these circuits. However, these comparisons were drawn under different conditions, including switching frequency and level number for the circuits. In addition, these comparisons do not include the use of SiC devices. We made an equitable comparison for a 100 kVa pole‐mounted STATCOM using SiC devices. We discuss the performance and characteristics of each circuit in terms of efficiency and volume. 相似文献
104.
105.
106.
A Method for Reducing the Dead‐Time Voltage and Impedance Voltage in a Series Voltage Compensator
下载免费PDF全文
![点击此处可从《Electrical Engineering in Japan》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Atsushi Nakata Masahiro Nozaki Akihiro Torii Akiteru Ueda 《Electrical Engineering in Japan》2014,186(3):85-93
Many research groups are developing series voltage compensators. In a series converter, since a transformer is used in series in the power system, the power system current flows into the voltage source inverter through the transformer. The inverter current, which is determined by the transformation ratio, gives rise to an error voltage that consists of a dead‐time voltage and an impedance voltage. The error voltage is generated even when the reference voltage is zero. This paper describes the mechanism by which the error voltage occurs and proposes a method for reducing the error voltage. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 85–93, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22333 相似文献
107.
108.
Susumu Fujii Masato Yoshiya Akuto Yumura Yohei Miyauchi Masahiro Tada Hideyuki Yasuda 《Journal of Electronic Materials》2014,43(6):1905-1915
The phonon thermal conductivity of misfit-layered Ca3Co4O9 has been calculated by perturbed molecular dynamics using a classical force field. Detailed numerical analyses reveal that, in spite of its smaller cross-sectional area, the CoO2 layer transports more heat than the thicker rock salt (RS) layer, although its local thermal conduction is more suppressed than in another layered cobaltite, Na x CoO2. The origins of these differences have been elucidated through careful examination of the atomic arrangements in each layer. Since thermal conduction in the RS layer can be reduced without deteriorating electronic properties for which the CoO2 layer is responsible, it is suggested that the RS layer should be modified to further suppress the overall in-plane thermal conductivity. Computational experiments with increasing number of Ca–O planes in the RS layer showed the opposite trend to what can be predicted based on the misfit between two dissimilar layers. Further analyses to reveal the origin of these unexpected results provide yet another strategy to further decrease the thermal conductivity, namely to control the dynamic interference between atoms across the interface between two layers. 相似文献
109.
Toshio Shimoo Masahiro Ito Kiyohito Okamura Michio Takeda 《Journal of the American Ceramic Society》2001,84(1):111-116
Electron-beam-cured polycarbosilane fibers were heat-treated at 673–1773 K in a tube evacuated to 1.3 × 10−1 Pa and then exposed at 1873 K in argon. The effect of vacuum heat treatment on improving the high-temperature stability of low-oxygen SiC fibers was investigated by examining gas evolution, grain growth, surface composition, tensile strength, and morphology. The fibers heat-treated at <1173 K lost strength, because of the vigorous generation of residual hydrogen. A minute amount of oxygen in the atmosphere caused the active oxidation of SiC during heat treatment at >1673 K, resulting in severe strength degradation for the as-heat-treated fibers. Vacuum heat treatment at 1573 K provided the best characteristics in low-oxygen SiC fibers. 相似文献
110.
Kumagai S. Yoshimura N. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2001,8(4):673-678
Tracking and erosion behaviors of high temperature vulcanized (HTV)-silicone rubber (SIR) of 0.5 to 6.0 mm thicknesses were investigated in order to obtain the optimum thickness for enhancing tracking and erosion resistance under various leakage current levels. Under low leakage current, thinner samples showed a higher tracking and erosion resistance, while under medium and high leakage current, thicker samples showed better resistance to these behaviors. The optimum thickness to prolong the time to tracking and erosion failure appeared in the range of 1.0 to 3.0 mm thickness. The content of an initial low molecular weight (LMW) silicone fluid was shown to be closely related to the development of leakage current and high temperature thermal spots. The results indicate that the sample thickness is crucial to the ability of HTV-SIR to withstand a large number of high temperature thermal spots under condition of high level leakage current 相似文献