全文获取类型
收费全文 | 2311篇 |
免费 | 56篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 104篇 |
化学工业 | 546篇 |
金属工艺 | 38篇 |
机械仪表 | 51篇 |
建筑科学 | 30篇 |
能源动力 | 73篇 |
轻工业 | 159篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 283篇 |
一般工业技术 | 443篇 |
冶金工业 | 415篇 |
原子能技术 | 58篇 |
自动化技术 | 162篇 |
出版年
2023年 | 16篇 |
2022年 | 24篇 |
2021年 | 43篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 32篇 |
2017年 | 28篇 |
2016年 | 47篇 |
2015年 | 28篇 |
2014年 | 65篇 |
2013年 | 125篇 |
2012年 | 71篇 |
2011年 | 130篇 |
2010年 | 109篇 |
2009年 | 83篇 |
2008年 | 104篇 |
2007年 | 94篇 |
2006年 | 75篇 |
2005年 | 90篇 |
2004年 | 82篇 |
2003年 | 51篇 |
2002年 | 48篇 |
2001年 | 38篇 |
2000年 | 51篇 |
1999年 | 41篇 |
1998年 | 157篇 |
1997年 | 101篇 |
1996年 | 76篇 |
1995年 | 50篇 |
1994年 | 28篇 |
1993年 | 44篇 |
1992年 | 32篇 |
1991年 | 41篇 |
1990年 | 32篇 |
1989年 | 31篇 |
1988年 | 29篇 |
1987年 | 13篇 |
1986年 | 30篇 |
1985年 | 27篇 |
1984年 | 13篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 17篇 |
1974年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有2372条查询结果,搜索用时 31 毫秒
61.
Zihan Ma Xiaofei Lu Sunghyun Park Tatsuya Shinagawa Masashi Okubo Kazuhiro Takanabe Atsuo Yamada 《Advanced functional materials》2023,33(25):2214466
Hydrogen is a promising alternative to fossil fuels that can reduce greenhouse gas emissions. Decoupled water electrolysis system using a reversible proton storage redox mediator, where the oxygen evolution reaction and hydrogen evolution reaction are separated in time and space, is an effective approach to producing hydrogen gas with high purity, high flexibility, and low cost. To realize fast hydrogen production in such a system, a redox mediator capable of releasing protons rapidly is required. Herein, α-MoO3, with an ultrafast proton transfer property that can be explained by a dense hydrogen bond network in the lattice oxygen arrays of HxMoO3, is examined as a high-rate redox mediator for fast hydrogen production in acidic electrolytes. The α-MoO3 redox mediator shows both a large capacity of 204 mAh g−1 and fast hydrogen production at a current rate of 10 A cm−2(≈153 A g−1), outperforming most of the previously reported solid-state redox mediators. 相似文献
62.
Artificial Life and Robotics - This study considers an autonomous mobile vehicle using SLAM technology in an unknown environment. The focused problem is the decrease of trajectory following... 相似文献
63.
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
64.
Greedy versus social: resource-competing oscillator network as a model of amoeba-based neurocomputer
A single-celled amoeboid organism, the true slime mold Physarum polycephalum, exhibits rich spatiotemporal oscillatory behavior and sophisticated computational capabilities. The authors previously created
a biocomputer that incorporates the organism as a computing substrate to search for solutions to combinatorial optimization
problems. With the assistance of optical feedback to implement a recurrent neural network model, the organism changes its
shape by alternately growing and withdrawing its photosensitive branches so that its body area can be maximized and the risk
of being illuminated can be minimized. In this way, the organism succeeded in finding the optimal solution to the four-city
traveling salesman problem with a high probability. However, it remains unclear how the organism collects, stores, and compares
information on light stimuli using the oscillatory dynamics. To study these points, we formulate an ordinary differential
equation model of the amoeba-based neurocomputer, considering the organism as a network of oscillators that compete for a
fixed amount of intracellular resource. The model, called the “Resource-Competing Oscillator Network (RCON) model,” reproduces
well the organism’s experimentally observed behavior, as it generates a number of spatiotemporal oscillation modes by keeping
the total sum of the resource constant. Designing the feedback rule properly, the RCON model comes to face a problem of optimizing
the allocation of the resource to its nodes. In the problem-solving process, “greedy” nodes having the highest competitiveness
are supposed to take more resource out of other nodes. However, the resource allocation pattern attained by the greedy nodes
cannot always achieve a “socially optimal” state in terms of the public cost. We prepare four test problems including a tricky
one in which the greedy pattern becomes “socially unfavorable” and investigate how the RCON model copes with these problems.
Comparing problem-solving performances of the oscillation modes, we show that there exist some modes often attain socially
favorable patterns without being trapped in the greedy one. 相似文献
65.
66.
Masashi WatanabeAuthor Vitae Yu EiwaAuthor VitaeSho TokunagaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):727-734
If microfluidic devices can be directly produced using printing techniques, the combination of microfluidics and printing techniques for other applications, such as printed electronics, will make all-printed highly-functionalized microfluidic devices possible. Therefore, we have made efforts to develop a technique for producing microfluidic devices using an inkjet printer. The microchannels that could be created using this technique were a kind of surface-directed channels that utilize the pinning effect of a triple line on a rough surface. In this study, we focused on what were the required properties of the printer ink during the wetting and drying processes of the ink. As a result, one of the properties required during the wetting process was that the advancing contact angle of the ink should be smaller than a certain value, which depended on the average volume of the ink drops ejected from the printhead and the number of drops per unit area. The receding contact angle should be smaller than about one third of each advancing angle. In addition, during the drying process, a small amount of surfactant added to the ink played a critical role in order to leave a continuous stain of the ink. As an application of this inkjet-printed channel, we also created a device for mixing aqueous solutions. 相似文献
67.
Amoeba-based Chaotic Neurocomputing: Combinatorial Optimization by Coupled Biological Oscillators 总被引:1,自引:0,他引:1
Masashi Aono Yoshito Hirata Masahiko Hara Kazuyuki Aihara 《New Generation Computing》2009,27(2):129-157
We demonstrate a neurocomputing system incorporating an amoeboid unicellular organism, the true slime mold Physarum, known to exhibit rich spatiotemporal oscillatory behavior and sophisticated computational capabilities. Introducing optical
feedback applied according to a recurrent neural network model, we induce that the amoeba’s photosensitive branches grow or
degenerate in a network-patterned chamber in search of an optimal solution to the traveling salesman problem (TSP), where
the solution corresponds to the amoeba’s stably relaxed configuration (shape), in which its body area is maximized while the
risk of being illuminated is minimized.Our system is capable of reaching the optimal solution of the four-city TSP with a
high probability. Moreover, our system can find more than one solution, because the amoeba can coordinate its branches’ oscillatory
movements to perform transitional behavior among multiple stable configurations by spontaneously switching between the stabilizing
and destabilizing modes. We show that the optimization capability is attributable to the amoeba’s fluctuating oscillatory
movements. Applying several surrogate data analyses, we present results suggesting that the amoeba can be characterized as
a set of coupled chaotic oscillators.
相似文献
Kazuyuki AiharaEmail: |
68.
Brain impediments such as dementia are a serious problem today. It would be very useful if software for private diagnosis
were available. In this paper, we show the effectiveness of the human random generation test (HRG) for such software, and
propose a set of four indices to be used for classifying the HRG data. Human-generated random numbers have strong characteristics
compared to computer-generated random numbers, and these are known to be correlated to the individual characters of the subjects.
However, analysis using the correlation dimension or HMM requires a long data sequence, and thus is not suitable for diagnoses.
We therefore focus on short sequences of HRG and search for effective indices to detect signs of brain disability hidden in
the HRG data. We studied data from subjects of different age groups, and successfully differentiated the data from the different
groups.
This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January
25–27, 2007 相似文献
69.
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
70.
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