全文获取类型
收费全文 | 2523篇 |
免费 | 49篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 155篇 |
综合类 | 4篇 |
化学工业 | 482篇 |
金属工艺 | 42篇 |
机械仪表 | 61篇 |
建筑科学 | 46篇 |
能源动力 | 110篇 |
轻工业 | 129篇 |
水利工程 | 8篇 |
石油天然气 | 2篇 |
无线电 | 327篇 |
一般工业技术 | 487篇 |
冶金工业 | 461篇 |
原子能技术 | 65篇 |
自动化技术 | 198篇 |
出版年
2023年 | 11篇 |
2022年 | 19篇 |
2021年 | 34篇 |
2020年 | 17篇 |
2019年 | 34篇 |
2018年 | 30篇 |
2017年 | 26篇 |
2016年 | 48篇 |
2015年 | 20篇 |
2014年 | 54篇 |
2013年 | 120篇 |
2012年 | 81篇 |
2011年 | 93篇 |
2010年 | 99篇 |
2009年 | 96篇 |
2008年 | 109篇 |
2007年 | 86篇 |
2006年 | 81篇 |
2005年 | 102篇 |
2004年 | 68篇 |
2003年 | 62篇 |
2002年 | 55篇 |
2001年 | 57篇 |
2000年 | 53篇 |
1999年 | 58篇 |
1998年 | 172篇 |
1997年 | 121篇 |
1996年 | 96篇 |
1995年 | 59篇 |
1994年 | 40篇 |
1993年 | 66篇 |
1992年 | 39篇 |
1991年 | 58篇 |
1990年 | 37篇 |
1989年 | 36篇 |
1988年 | 31篇 |
1987年 | 18篇 |
1986年 | 40篇 |
1985年 | 39篇 |
1984年 | 17篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 21篇 |
1980年 | 20篇 |
1979年 | 13篇 |
1978年 | 18篇 |
1977年 | 20篇 |
1976年 | 25篇 |
1974年 | 8篇 |
1972年 | 5篇 |
排序方式: 共有2577条查询结果,搜索用时 15 毫秒
31.
A data-driven design method for a cascade control system is proposed. The cascade control system consists of inner and outer loops, where the control interval of the outer loop is an integer multiple of the inner loop; hence, the system is a dual-rate system. In the proposed method, controllers in the inner and outer loops are designed based on one-shot data. In such a dual-rate cascade system, since the controllers are designed using different data-rate signals, the lifting technique is applied to align the dual-rate data. To show its effectiveness, the proposed method is compared with a conventional single-rate cascade control method, and numerical simulations and experiments are presented to examine servo and regulation performance. 相似文献
32.
33.
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
34.
A simple and effective technique for synchronizing two independent Ti: sapphire lasers was developed and used for difference-frequency generation. By control of pump intensity, buildup times of these lasers were adjusted to coincide for any combination of wavelengths that was needed for the production of a desired difference frequency. Synchronized pulses were mixed at a AgGaS(2) crystal, producing infrared pulses from 6.2 to 9.7 μm. Characteristic features of the method as well as its possible extension of the tuning range are discussed. 相似文献
35.
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
36.
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
37.
Isao Kobayashi Yoshihiro Wada Kunihiko Uemura Mitsutoshi Nakajima 《Microfluidics and nanofluidics》2008,5(5):677-687
This study investigated the generation of oil drops using new symmetric and asymmetric through-hole-array devices made of
stainless steel. The through-hole-array devices were built by piling up six stainless-steel plates, each having circular micro-holes
with a diameter of 300 or 500 μm or micro-slots with a shorter line of 300 or 500 μm. Drops were generated by injecting a
dispersed phase (refined soybean oil) via the through-hole array into a compartment filled with a continuous phase (Milli-Q
water solution containing one of two emulsifiers). The drop detachment from symmetric and asymmetric through holes was observed
in real time and analyzed. Uniform oil drops with average diameters of 1.0–4.1 mm and coefficients of variation of typically
less than 6% were generated using symmetric and asymmetric through-hole-array devices. The resultant drop diameters for asymmetric
through-hole arrays were significantly smaller than those for symmetric through-hole arrays. This paper also discusses experimental
results regarding the effects of the microstructure, the dimensions of the through holes, and the type of emulsifier on drop
generation and the resultant drop diameter. 相似文献
38.
Straight-through microchannel devices for generating monodisperse emulsion droplets several microns in size 总被引:1,自引:1,他引:0
Isao Kobayashi Takayuki Takano Ryutaro Maeda Yoshihiro Wada Kunihiko Uemura Mitsutoshi Nakajima 《Microfluidics and nanofluidics》2008,4(3):167-177
The authors recently proposed a promising technique for producing monodisperse emulsions using a straight-through microchannel
(MC) device composed of an array of microfabricated oblong holes. This research developed new straight-through MC devices
with tens of thousands of oblong channels of several microns in size on a silicon-on-insulator plate, and investigated the
emulsification characteristics using the microfabricated straight-through MC devices. Monodisperse oil-in-water (O/W) and
W/O emulsions with average droplet diameters of 4.4–9.8 μm and coefficients of variation of less than 6% were stably produced
using surface-treated straight-through MC devices that included uniformly sized oblong channels with equivalent diameters
of 1.7–5.4 μm. The droplet size of the resultant emulsions depended greatly on the size of the preceding oblong channels.
The emulsification process using the straight-through MC devices developed in this research had very high apparent energy
efficiencies of 47–60%, defined as (actual energy input applied to droplet generation/theoretical minimum energy input necessary
for making droplets) × 100. Straight-through MC devices with numerous oblong microfluidic channels also have great potential
for increasing the productivity of monodisperse fine emulsions. 相似文献
39.
40.