全文获取类型
收费全文 | 1470篇 |
免费 | 39篇 |
专业分类
电工技术 | 112篇 |
综合类 | 5篇 |
化学工业 | 309篇 |
金属工艺 | 29篇 |
机械仪表 | 39篇 |
建筑科学 | 34篇 |
能源动力 | 93篇 |
轻工业 | 70篇 |
水利工程 | 3篇 |
无线电 | 148篇 |
一般工业技术 | 302篇 |
冶金工业 | 161篇 |
原子能技术 | 37篇 |
自动化技术 | 167篇 |
出版年
2023年 | 4篇 |
2022年 | 17篇 |
2021年 | 21篇 |
2020年 | 10篇 |
2019年 | 20篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 29篇 |
2015年 | 21篇 |
2014年 | 46篇 |
2013年 | 82篇 |
2012年 | 58篇 |
2011年 | 61篇 |
2010年 | 67篇 |
2009年 | 60篇 |
2008年 | 70篇 |
2007年 | 66篇 |
2006年 | 55篇 |
2005年 | 63篇 |
2004年 | 45篇 |
2003年 | 44篇 |
2002年 | 39篇 |
2001年 | 34篇 |
2000年 | 23篇 |
1999年 | 30篇 |
1998年 | 62篇 |
1997年 | 59篇 |
1996年 | 48篇 |
1995年 | 30篇 |
1994年 | 28篇 |
1993年 | 37篇 |
1992年 | 14篇 |
1991年 | 25篇 |
1990年 | 15篇 |
1989年 | 20篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 21篇 |
1985年 | 23篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1974年 | 4篇 |
1972年 | 3篇 |
排序方式: 共有1509条查询结果,搜索用时 15 毫秒
31.
32.
Field‐Effect Transistors: Integration of Organic Electrochemical and Field‐Effect Transistors for Ultraflexible,High Temporal Resolution Electrophysiology Arrays (Adv. Mater. 44/2016)
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)
33.
Takayuki Goto Takao Watanabe Kyoichi Kinoshita Azusa Matsuda Masafumi Sera Tetsuo Fukase 《Journal of Low Temperature Physics》1996,105(3-4):401-406
Cu-NMR spectra and the nuclear spin-lattice relaxation rate T
1
-1
have been studied intensively on the bilayer type high-Tc cuprate La1.89Ca1.11Cu2O6+ (La2126). The resonance line shift showed a monotonic decrease with lowering temperature in the normal state, indicating that this compound belongs to the lightly-doped region. The Curie-Weiss temperature dependence of (T1T)–1 in the normal state shows that the pseudo spin-gap does not always exist in the light-doped bilayer systems. 相似文献
34.
35.
Scale free graphs have attracted attention by their non-uniform structure that can be used as a model for various social and physical networks. In this paper, we propose a natural and simple random model for generating scale free interval graphs. The model generates a set of intervals randomly under a certain distribution, which defines a random interval graph. The main advantage of the model is its simpleness. The structure/properties of generated graphs are analyzable by relatively simple probabilistic and/or combinatorial arguments, which is different from many other models. Based on such arguments, we show for our random interval graph that its degree distribution follows a power law, and that it has a large average clustering coefficient. 相似文献
36.
Shih-Ying LinShi-Jinn Horng Tzong-Wann KaoChin-Shyurng Fahn Pingzhi FanYuan-Hsin Chen Muhammad Khurram KhanAnu Bourgeois Takao Terano 《Image and vision computing》2011,29(4):272-285
Traditionally, the block-based medial axis transform (BB-MAT) and the chessboard distance transform (CDT) were usually viewed as two completely different image computation problems, especially for three dimensional (3D) space. In fact, there exist some equivalent properties between them. The relationship between both of them is first derived and proved in this paper. One of the significant properties is that CDT for 3D binary image V is equal to BB-MAT for image V' where it denotes the inverse image of V. In a parallel algorithm, a cost is defined as the product of the time complexity and the number of processors used. The main contribution of this work is to reduce the costs of 3D BB-MAT and 3D CDT problems proposed by Wang [65]. Based on the reverse-dominance technique which is redefined from dominance concept, we achieve the computation of the 3D CDT problem by implementing the 3D BB-MAT algorithm first. For a 3D binary image of size N3, our parallel algorithm can be run in O(logN) time using N3 processors on the concurrent read exclusive write (CREW) parallel random access machine (PRAM) model to solve both 3D BB-MAT and 3D CDT problems, respectively. The presented results for the cost are reduced in comparison with those of Wang's. To the best of our knowledge, this work is the lowest costs for the 3D BB-MAT and 3D CDT algorithms known. In parallel algorithms, the running time can be divided into computation time and communication time. The experimental results of the running, communication and computation times for the different problem sizes are implemented in an HP Superdome with SMP/CC-NUMA (symmetric multiprocessor/cache coherent non-uniform memory access) architecture. We conclude that the parallel computer (i.e., SMP/CC-NUMA architecture or cluster system) is more suitable for solving problems with a large amount of input size. 相似文献
37.
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
38.
For systems with uncertainties, lots of PID parameter tuning methods have been proposed from the view point of the robust stability theory. However, the control performance becomes conservative using robust PID controllers. In this paper, a new two‐degree‐of‐freedom (2DOF) controller, which can improve the tracking properties, is proposed for nonlinear systems. According to the proposed method, the prefilter is designed as the PD compensator whose control parameters are tuned by the idea of a memory‐based modeling (MBM) method. Since the MBM method is a type of local modeling methods for nonlinear systems, PD parameters can be tuned adequately in an online manner corresponding to nonlinear properties. Finally, the effectiveness of the newly proposed control scheme is numerically evaluated on a simulation example. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
39.
Satoru Maegawa Takao Mizusaki Yutaka Hirayoshi Tadashi Kusumoto Akira Hirai 《Journal of Low Temperature Physics》1980,39(1-2):151-171
Nuclear spin-lattice relaxation properties of hcp solid 3He with 4He impurities have been studied. At temperatures below the exchange plateau region, three kinds of relaxation time were observed. To analyze the data, a phenomenological four-bath model was developed, the four baths being the Zeeman bath, the phonon bath, an X-bath, and a Y-bath. The X-bath consists of the exchange bath and a part of the 4He-4He elastic interaction bath. The Y-bath is the main part of the elastic interaction bath. We measured the concentration dependence of the energy constants of all the baths, as well as the temperature and concentration dependences of the three kinds of relaxation time. The relaxation behavior corresponding to the process between the X-bath and the Y-bath could not be expressed by a single exponential function of time and the relaxation rate was strongly dependent on the concentration. This process may be related to the internal thermal equilibrium process within the elastic interaction bath. The impurity-dependent relaxation time between the X-bath and the phonon bath had a temperature dependence of T
–n with n = 7.4±0.3. 相似文献
40.