全文获取类型
收费全文 | 6516篇 |
免费 | 136篇 |
国内免费 | 29篇 |
专业分类
电工技术 | 453篇 |
综合类 | 17篇 |
化学工业 | 1756篇 |
金属工艺 | 159篇 |
机械仪表 | 157篇 |
建筑科学 | 205篇 |
矿业工程 | 1篇 |
能源动力 | 275篇 |
轻工业 | 595篇 |
水利工程 | 27篇 |
石油天然气 | 9篇 |
无线电 | 474篇 |
一般工业技术 | 1118篇 |
冶金工业 | 556篇 |
原子能技术 | 243篇 |
自动化技术 | 636篇 |
出版年
2023年 | 35篇 |
2022年 | 64篇 |
2021年 | 109篇 |
2020年 | 59篇 |
2019年 | 76篇 |
2018年 | 80篇 |
2017年 | 75篇 |
2016年 | 136篇 |
2015年 | 90篇 |
2014年 | 167篇 |
2013年 | 353篇 |
2012年 | 221篇 |
2011年 | 346篇 |
2010年 | 288篇 |
2009年 | 303篇 |
2008年 | 358篇 |
2007年 | 302篇 |
2006年 | 233篇 |
2005年 | 252篇 |
2004年 | 212篇 |
2003年 | 184篇 |
2002年 | 194篇 |
2001年 | 127篇 |
2000年 | 130篇 |
1999年 | 133篇 |
1998年 | 254篇 |
1997年 | 170篇 |
1996年 | 138篇 |
1995年 | 104篇 |
1994年 | 121篇 |
1993年 | 104篇 |
1992年 | 82篇 |
1991年 | 96篇 |
1990年 | 79篇 |
1989年 | 101篇 |
1988年 | 81篇 |
1987年 | 51篇 |
1986年 | 84篇 |
1985年 | 72篇 |
1984年 | 61篇 |
1983年 | 69篇 |
1982年 | 74篇 |
1981年 | 65篇 |
1980年 | 53篇 |
1979年 | 53篇 |
1978年 | 49篇 |
1977年 | 36篇 |
1976年 | 51篇 |
1975年 | 26篇 |
1973年 | 21篇 |
排序方式: 共有6681条查询结果,搜索用时 21 毫秒
91.
Vibration control of load for rotary crane system using neural network with GA-based training 总被引:4,自引:0,他引:4
Kunihiko Nakazono Kouhei Ohnishi Hiroshi Kinjo Tetsuhiko Yamamoto 《Artificial Life and Robotics》2008,13(1):98-101
A neuro-controller for vibration control of load in a rotary crane system is proposed involving the rotation about the vertical
axis only. As in a nonholonomic system, the vibration control method using a static continuous state feedback cannot stabilize
the load swing. It is necessary to design a time-varying feedback controller or a discontinuous feedback controller. We propose
a simple three-layered neural network as a controller (NC) with genetic algorithm-based (GA-based) training in order to control
load swing suppression for the rotary crane system. The NC is trained by a real-coded GA, which substantially simplifies the
design of the controller. It appeared that a control scheme with performance comparable to conventional methods can be obtained
by a relatively simple approach.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
92.
Makoto Sakamoto Kaoru Kajisa Naoko Tomozoe Takao Ito Hiroshi Furutani Michio Kono Satoshi Ikeda 《Artificial Life and Robotics》2008,13(1):61-64
In 1997, C.R. Dyer and A. Rosenfeld introduced an acceptor on a two-dimensional pattern (or tape), called the pyramid cellular acceptor, and demonstrated that many useful recognition tasks are executed by pyramid cellular acceptors in time proportional to the
logarithm of the diameter of the input. They also introduced a bottom-up pyramid cellular acceptor which is a restricted version of the pyramid cellular acceptor, and proposed some interesting open problems of the bottom-up
pyramid cellular acceptors. On the other hand, we think that the study of threedimensional automata has been meaningful as
the computational model of three-dimensional information processing such as computer vision, robotics, and so forth. In this
paper, we investigate about bottom-up pyramid cellular acceptors with three-dimensional layers, and show their some accepting
powers.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
93.
Yamamoto T Kato R Yamamoto HM Fukaya A Yamasawa K Takahashi I Akutsu H Akutsu-Sato A Day P 《The Review of scientific instruments》2007,78(8):083906
We have developed a technique for the anisotropic extension of fragile molecular crystals. The pressure medium and the instrument, which extends the pressure medium, are both made from epoxy resin. Since the thermal contraction of our instrument is identical to that of the pressure medium, the strain applied to the pressure medium has no temperature dependence down to 2 K. Therefore, the degree of extension applied to the single crystal at low temperatures is uniquely determined from the degree of extension in the pressure medium and thermal contractions of the epoxy resin and the single crystal at ambient pressure. Using this novel instrument, we have measured the temperature dependence of the electrical resistance of metallic, superconducting, and insulating materials. The experimental results are discussed from the viewpoint of the extension (compression) of the lattice constants along the parallel (perpendicular) direction. 相似文献
94.
Kanamaru Y Gota H Fujimoto K Ikeyama T Asai T Takahashi T Nogi Y 《The Review of scientific instruments》2007,78(3):036105
A magnetic probe array is constructed to measure precisely the spatial structure of a small fluctuating field included in a strong confinement field that varies with time. To exclude the effect of the confinement field, the magnetic probes consisting of figure-eight-wound coils are prepared. The spatial structure of the fluctuating field is obtained from a Fourier analysis of the probe signal. It is found that the probe array is more sensitive to the fluctuating field with a high mode number than that with a low mode number. An experimental demonstration of the present method is attempted using a field-reversed configuration plasma, where the fluctuating field with 0.1% of the confinement field is successfully detected. 相似文献
95.
Given a digraph (or an undirected graph) G=(V,E) with a set V of vertices v with nonnegative real costs w(v), and a set E of edges and a positive integer k, we deal with the problem of finding a minimum cost subset SV such that, for each vertex vV−S, there are k vertex-disjoint paths from S to v. In this paper, we show that the problem can be solved by a greedy algorithm in
time in a digraph (or in
time in an undirected graph), where n=|V| and m=|E|. Based on this, given a digraph and two integers k and ℓ, we also give a polynomial time algorithm for finding a minimum cost subset SV such that for each vertex vV−S, there are k vertex-disjoint paths from S to v as well as ℓ vertex-disjoint paths from v to S. 相似文献
96.
97.
This paper proposes a parallel processing model of the Prolog language. The model modifies Or-parallelism by introducing the “process bundle” as a candidate for simultaneous execution. The Process bundle is a subset of backtrack points stacked in depth-first execution. The process bundle includes one or more backtrack points, so it provides a longer process life cycle than the Or-parallel process. A process bundle is dispatched when an idle processor requests a job from an executing processor. The executing processor dispatches a message containing the full environment by which the idle processor can execute the process without any communication with other processors. 相似文献
98.
Hiroshi Namaizawa 《Journal of Low Temperature Physics》1978,31(5-6):747-762
A self-consistent theory is proposed for anisotropic quantum solids such as dense helium monolayers adsorbed onto graphite, based upon the reactionmatrix formalism. The effect of the excitations normal to the adsorption plane is fully included in the ground-state as well as in the vibrational properties. Dispersion relations are derived both for the in-plane and out-of-plane vibrational modes, and the coupling of the two modes is studied as well. 相似文献
99.
Akihiko Nagata Osamu Izumi Kōshichi Noto Hiroshi Hirayama 《Journal of Materials Science》1978,13(4):731-738
The dilute Cu-Nb-Sn alloys containing small amounts of Nb and Sn less than 1 at % exhibited superconductivity after quenching from the liquid state and ageing. The best superconducting properties (
andJ
c=130 A cm–2) in a Cu-0.30 at % Nb 0.15 at % Sn alloy were obtained when the sample was aged at 550° C for 384 h. This sample exhibited a structure of fine Nb3Sn precipitates of 200 to 500Å diameter distributed homogeneously in the Cu matrix, and therefore it was concluded that superconductivity in these alloys resulted from the proximity effect of Nb3Sn particles. In spite of the similar structure obtained by ageing at 800° C, the Cu-Nb-Sn alloys showed inferior superconducting properties compared to the Cu-0.4 at % Nb alloy and this would be explained qualitatively by the difference in the mean free path in the two alloys. 相似文献
100.
This letter presents a new algorithm for blind dereverberation and echo cancellation based on independent component analysis (ICA) for actual acoustic signals. We focus on frequency domain ICA (FD-ICA) because its computational cost and speed of learning convergence are sufficiently reasonable for practical applications such as hands-free speech recognition. In applying conventional FD-ICA as a preprocessing of automatic speech recognition in noisy environments, one of the most critical problems is how to cope with reverberations. To extract a clean signal from the reverberant observation, we model the separation process in the short-time Fourier transform domain and apply the multiple input/output inverse-filtering theorem (MINT) to the FD-ICA separation model. A naive implementation of this method is computationally expensive, because its time complexity is the second order of reverberation time. Therefore, the main issue in dereverberation is to reduce the high computational cost of ICA. In this letter, we reduce the computational complexity to the linear order of the reverberation time by using two techniques: (1) a separation model based on the independence of delayed observed signals with MINT and (2) spatial sphering for preprocessing. Experiments show that the computational cost grows in proportion to the linear order of the reverberation time and that our method improves the word correctness of automatic speech recognition by 10 to 20 points in a RT??= 670 ms reverberant environment. 相似文献