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排序方式: 共有1006条查询结果,搜索用时 15 毫秒
31.
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
32.
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
33.
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
34.
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: |
35.
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
36.
Koji Matsumoto Ken Oikawa Masashi Okada Yoshikazu Teraoka Tetsuo Kawagoe 《International Journal of Refrigeration》2006,29(6):1010
This study focuses on an emulsion as a new thermal storage material for ice storage. Two types of emulsions were formed using an oil–water mixture with a small amount of additive. A silicone, light and lump oils were used. The water contents of the emulsions were 70, 80 and 90%. The additive was an amino group modified silicone oil. No depression of freezing point was observed for the emulsions because of their hydrophobic properties. In order to determine the structure of the emulsions, their electrical resistances were measured. Moreover, components of the liquids separating from the emulsions were analyzed. The results indicated that one emulsion was a W/O type emulsion, while the other was an O/W type. Finally, adaptability of the two emulsions to ice storage was discussed, it was concluded that a high performance ice slurry could be formed by the W/O type emulsion. 相似文献
37.
Toshihiko Hirama Masashi Goto Keiji Shiba Toshio Kobayashi Ryozo Tanaka Shizuo Tsurumaki Katsuki Takiguchi Hiroshi Akiyama 《Nuclear Engineering and Design》2005,235(13):7
A 1/8-scale model was constructed of a reinforced concrete containment vessel (RCCV) used in the latest advanced boiling water reactors (ABWR). Shaking table tests were conducted on it with input motions corresponding to or exceeding a design earthquake assumed for a real Nuclear Power Plant.The objectives of the tests were to verify the structural integrity and the leak-proof functional soundness of the RCCV subjected to design earthquakes, and to determine the ultimate strength and seismic margin by an excitation that led to the model's collapse. The model, the test sequence and the pressure and leak test results were addressed in Part 1. The shaking table test method, the input motions and the test results, including the transition of the model's stiffness, natural frequencies and damping factors and the effects of vertical input motions and internal pressure on the model's characteristics and behavior, the load–deformation, the ultimate strength, the failure mode of the reinforced concrete portion and the liner plate are described here. The seismic safety margin that was evaluated by the energy input during the failure test to a design basis earthquake will be described in Part 3. The analytical results of simulation using the multi-lumped mass model will be described in Part 4. 相似文献
38.
Noriaki Murakami Koji Arafune Tadanobu Koyama Yoshimi Momose Tetsuo Ozawa Yasunori Okano Sadik Dost Le. H. Dao Masashi Kumagawa Yasuhiro Hayakawa 《Microgravity science and technology》2005,16(1-4):79-83
The effect of gravity on dissolution of GaSb in InSb melt and growth of InGaSb was experimentally investigated. Experiments were carried out in a GaSb(seed)/InSb/GaSb(feed) sandwich system under an imposed temperature gradient. In the experiments, the GaSb feed crystal dissolved into the InSb melt to supply the required GaSb component for the growth of In0.1Ga0.9Sb crystal. Two parameters were considered: (1) the inclination angle (θ) of the sample for gravity as 0° and 53°, and (2) the sample diameter (D) as 9 mm and 5mm. When θ was 0°, the interface was almost flat, indicating that convection was axisymmetric and stable. Whereas the interface was distorted towards gravitational direction when θ was 53°, indicating that solutal convection was dominant. The decrease of growth temperature and sample diameter reduced the distortion of interface and the dissolution amount of GaSb feed. The homogeneous crystals were grown at the initial growth stage by supplying the GaSb component during growth. 相似文献
39.
Hiroyuki Sasakura Yoshiya Akagi Masashi Tanaka Shigeki Tsukui Motoaki Adachi 《Journal of Superconductivity and Novel Magnetism》2012,25(2):305-309
New Pb-based 1222 cuprates containing phosphorus have been synthesized in the (Pb0.75P0.25)Sr2- (RE2–x–y
Ce
x
Sr
y
)Cu2O
z
(RE = Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y) systems. The almost-single phase samples are obtained for 0.5≤x≤1.0 and y=0.1 in the cases of RE = Nd, Dy, Ho, Er, Tm, Yb and Y, while for 0.3≤x≤1.0 and y=0.1 in the cases of RE = Sm, Eu and Gd. The samples crystallize in a tetragonal lattice, the lattice parameters a and c are decreasing with the decrease of the ionic radius of the RE element. Even after annealing under 143 atm O2 atmosphere at 400 °C, almost all the samples with the common values x=0.5 and y=0.1 are semiconductors with a transport process followed by three-dimensional variable range hopping. However, the samples
of RE = Sm, Eu and Gd, which are of almost single 1222 phase, even for x=0.3 and y=0.1, show superconductivity with the onsets at about 25 K, 20 K and 22 K, respectively. Through this study, we find very
important procedure for discovery of new superconducting 1222 compound. 相似文献
40.
Masashi Morishita 《Journal of Low Temperature Physics》2013,171(5-6):664-669
The heat capacity of dilute 3He–4He films is measured to clarify whether the second adsorbed layer of 4He films on graphite solidify into the so-called “4/7 phase.” The 3He areal density is fixed at 0.2 nm?2, whereas the 4He areal density is gradually increased. The measured heat capacities suddenly decrease with an increasing areal density approaching that of the 4/7 phase. Above the areal density of the 4/7 phase, the heat capacities do not reduce completely to zero and have finite values. The behavior of the heat capacity does not change over a rather wide areal density regime, although it suddenly increases or recovers at around the areal density of the third-layer promotion. These behaviors can be interpreted as the separation of 3He–4He mixture films into a 3He-rich phase and a 4He-rich phase, with the 3He-rich phase solidifying into the 4/7 phase and the 4He-rich phase remaining fluid below the areal density of the third-layer promotion. These observations strongly suggest that a 4He film adsorbed on a graphite surface does not solidify into the 4/7 phase. 相似文献