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1.
Application of the sputtering technique to (Al2O3)xBi100–x and (AIN)x Bi100–x (x = 0 to 100%) has been found to result in the formation of a duplex material consisting of hexagonal bismuth particles dispersed finely and homogeneously in amorphous AlxOy and AlxNy matrices. The particle size and interparticle distance of the bismuth phase were about 5 to 140nm and 5 to 35 nm. The duplex alloys have high electrical resistivities ranging from 1.82 × 103 to 3.16 × 105 cm combined with a negative temperature-dependent resistivity of 148 to 342% of 273. Furthermore, all the Al-O-Bi and Al-N-Bi alloys have been found to exhibit a positive magnetoresistive change and the maximum value, (H), at 4.2 K and 7.5T reaches 5.85 × 104 cm for (Al-O)65.7Bi34.3 and 1.99 × 105 cm for (Al-N)69.7 Bi30.3. The large magnetoresistivities are probably due to the unique sputtered structure consisting of metallic bismuth particles with a long mean free path of electrons embedded finely and homogeneously in amorphous AlxOy or AlxNy matrix, resulting in the large difference of the relaxation times (different mobilities) of electron carriers. It has thus been demonstrated that the oxide- or nitride-based composite materials exhibiting large magnetoresistivities, which cannot be achieved in metallic composite materials, are obtained by sputtering simultaneously Al2O3 or AIN and bismuth which is immiscible to aluminium. 相似文献
2.
The plasmodium of Physarum polycephalum is a unicellular and multinuclear giant amoeba that has an amorphous cell body. To clearly observe how the plasmodium makes decisions in its motile and exploratory behaviours, we developed a new experimental system to pseudo-discretize the motility of the organism. In our experimental space that has agar surfaces arranged in a two-dimensional lattice, the continuous and omnidirectional movement of the plasmodium was limited to the stepwise one, and the direction of the locomotion was also limited to four neighbours. In such an experimental system, a cellular automata-like system was constructed using the living cell. We further analysed the exploratory behaviours of the plasmodium by duplicating the experimental results in the simulation models of cellular automata. As a result, it was revealed that the behaviours of the plasmodium are not reproduced by only local state transition rules; and for the reproduction, a kind of historical rule setting is needed. 相似文献
3.
Shinichi Shirakawa Tomoharu Nagao 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2016,20(10):3787-3802
Evolutionary computation is a research field dealing with black-box and complex optimization problems whose fitness landscapes are usually unknown in advance. It is difficult to select an appropriate evolutionary algorithm and parameters for a given problem due to the black-box setting although many evolutionary algorithms have been developed. In this context, several landscape features have been proposed and their usefulness examined for understanding the problem. In this paper, we propose a novel feature vector by focusing on the local landscape in order to characterize the fitness landscape. The proposed landscape features are a vector form and composed of a histogram of quantized local landscape features. We introduce two implementation methods of this concept, called the bag of local landscape patterns (BoLLP) and the bag of evolvability (BoEvo). The BoLLP uses the fitness pattern of the neighbors of a certain candidate solution, and the BoEvo uses the number of better candidate solutions in the neighbors as the local landscape features. Furthermore, the hierarchical versions of the BoLLP and the BoEvo, concatenated feature vectors with different sample sizes, are considered to capture the landscape characteristic with various resolutions. We extract the proposed landscape feature vectors from well-known continuous optimization benchmark functions and the BBOB benchmark function set to investigate their properties; the visualization of the proposed landscape features, clustering and running time prediction experiments are conducted. Then the effectiveness of the proposed landscape features for the fitness landscape analysis is discussed based on the experimental results. 相似文献
4.
The electronic structures of polyfluoroacetylene and polydifluoroacetylene are discussed on the basis of the tight-binding LCAO-SCF-MO calculations under the CNDO/2 approximations. A method of preparation of these polymers is also proposed. If they can be successfully prepared, they will be promising candidates for new electric conducting materials as alternatives to polyacetylene. 相似文献
5.
An exact analysis of the dynamic problem on the thermal displacements and stresses of cylindrical shells subjected to instantaneous heating is carried out. Equations of motion for cylindrical shells, including the thermal effects, are reduced and solved by using the Fourier and Laplace transformation methods, after obtaining the temperature distribution determined from the nonstationary equation of heat conduction for a shell under a prescribed temperature field. Numerical results are presented for the thermal displacement and stresses due to the time variation together with the quasistatic ones. 相似文献
6.
The macroscopic morphology of as-prepared polyacetylene depends on the concentration of the catalyst system. At high catalyst concentration, polymerization occurs on the free surface of the catalyst solution to form a polyacetylene film which retards further polymerization because of the limited diffusion of acetylene monomer through the film. At lower concentrations, however, successive diffusion and polymerization is possible yielding a gelatinous mass. A continuous mass does not form at an extremely low concentration; the product is flock or powder. Despite these differences in macroscopic morphology, electron micrographs show that the fibrillar structure is a common feature of all forms of polyacetylene. However, the average fibril diameter of 200 Å may depend on the polymerization conditions. Orientation of the fibrils by combined mechanical and thermal treatment is possible to produce highly stretch-aligned films which show anisotropic properties. 相似文献
7.
We investigated author information in scientific articles by approximately 7,000 researchers for a quantitative analysis of
researchers’ international mobility. From top journals, we traced the movements of more than 2,200 researchers in the research
domains of robotics, computer vision and electron devices. We categorized countries’ characteristics for the balance between
the inflow and the outflow of researchers moving internationally. Flow patterns of international mobility confirm that the
United States, China and India exhibit the greatest global flows of researchers, with Singapore and Hong Kong attracting remarkable
numbers of researchers from other countries. International mobility focusing on institutions reveals that universities in
Singapore receive as many foreign researchers as do research universities in the United States. Furthermore, firms and international
collaborative research institutes act as alternative receivers to the universities in the electron devices research domain. 相似文献
8.
Speed-up of computing time for numerical analysis of particle charging process by using discrete element method 总被引:1,自引:0,他引:1
Hiroshi Mio Masatoshi Akashi Yoshiyuki Shirakawa Shinroku Matsuzaki 《Chemical engineering science》2009,64(5):1019-1026
The objective of this paper is to improve the computing time for numerical analysis of particle charging process by using discrete element method. The rule for ignoring the calculations of contact forces and updating trajectories of unmoved particles were discussed. When the relative displacement of a particle within certain calculation steps became less than 0.1% of particle radius, this particle was determined to be unmoved and the calculations of this particle were ignored. The computing time was improved significantly when this new method was used, and its calculation speed was more than two times faster than that of original. It was found that this speed-up method is more useful for the cases that the particle becomes unmoved in short time or the height of charged bed is large. The simulation of charging process in an industrial-scale surge hopper was studied by using new method, the calculation speed became 2.88 times faster than that of original, and the quite similar particle size segregation between original and new methods was given. This new method for speed-up of the charging process in DEM is very useful, and the charging processes of the industrial scale storages can be simulated by using this method. 相似文献
9.
Quantitative analysis of collaborative and mobility networks 总被引:1,自引:0,他引:1
This study proposes a quantitative analysis of researcher mobility (i.e. transfer from one institution to another) and collaborative
networks on the basis of author background data extracted from biographical notes in scientific articles to identify connections
that are not revealed via simple co-authorship analysis. Using a top-ranked journal in the field of computer vision, we create
a layered network that describes various aspects of author backgrounds, demonstrating a geographical distribution of institutions.
We classify networks according to various dimensions including authors, institutions and countries. The results of the quantitative
analysis indicate that mobility networks extend beyond the typical collaborative networks describing institutional and international
relationships. We also discuss sectoral collaboration considering the mobility networks. Our findings indicate a limitation
of collaborative analysis based on bibliometric data and the importance of tracing researcher mobility within potential networks
to identify the true nature of scientific collaboration. 相似文献
10.
M. Furukawa S. Urano N. Tsuboniwa S. Shirakawa E. Yamanaka M. Yabuta 《Progress in Organic Coatings》1994,24(1-4):101-113
N-Methacryloylcarbamate (N-MAC), which is an original monomer of Nippon Paint, is a heterofunctional monomer which has a polymerizable double bond and an acylcarbamate group in the same molecule. It has four characteristic properties, which have been developed for use in coatings. These are: a molecular weight that can be controlled easily by the amount of radical initiator used irrespective of the kind of acylcarbamate; the reactivity of the acylcarbamate group in the polymer is lower with an alcohol than in a monomer. However, the reactivity of the acylcarbamate group in the polymer with alcohol is much higher than that of carbamate group with alcohol; a curing temperature dependent on the kind of acylcarbamate group; and an acylcarbamate group that can react with a low nucleophilic active hydrogen such as that of a secondary alcohol. An electrodeposition paint has been developed from these properties since the activated acylcarbamate group in the N-MAC polymer makes it possible to design a low temperature crosslinking system, the flexibility in design of the main resin with respect to the active hydrogen makes it possible to improve the storage stability because of high reactivities of N-MAC polymer with active hydrogen compounds, and a core/shell structure makes it possible to make low temperature crosslinking compatible with good storage stability. 相似文献