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91.
92.
Enterprise Architecture (EA) is a relatively new domain that is rapidly developing. “The primary reason for developing EA
is to support business by providing the fundamental technology and process structure for an IT strategy” [TOGAF]. EA models
have to model enterprises facets that span from marketing to IT. As a result, EA models tend to become large. Large EA models
create a problem for model management. Concern-based design methods (CBDMs) aim to solve this problem by considering EA models
as a composition of smaller, manageable parts—concerns. There are dozens of different CBDMs that can be used in the context
of EA: from very generic methods to specific methods for business modeling or IT implementations. This variety of methods
can cause two problems for those who develop and use innovative CBDMs in the field of Enterprise Architecture (EA). The first
problem is to choose specific CBDMs that can be used in a given EA methodology: this is a problem for researchers who develop
their own EA methodology. The second problem is to find similar methods (with the same problem domain or with similar frameworks)
in order to make a comparative analysis with these methods: this is a problem of researchers who develop their own CBDMs related
to a specific problem domain in EA (such as business process modeling or aspect oriented programming). We aim to address both
of these problems by means of a definition of generic Requirements for CBDMs based on the system inquiry. We use these requirements
to classify twenty CBDMs in the context of EA. We conclude with a short discussion about trends that we have observed in the
field of concern-based design and modeling. 相似文献
93.
Pavel Grigorenko Ando Saabas Enn Tyugu 《Electronic Notes in Theoretical Computer Science》2005,141(4):137
A compiler-compiler for visual languages is presented. It has been designed as a framework for building visual programming environments that translate schemas into textual representation as well as into programs representing the deep meaning of schemas. The deep semantics is implemented by applying attribute grammars to schema languages; attribute dependencies are implemented as methods of Java classes. Unlike compiler-compilers of textual languages, a large part of the framework is needed for support of interactive usage of a visual language. 相似文献
94.
Improved pump-beam distribution in a diode side-pumped solid-state laser with a highly diffuse, cross-axis beam delivery system 总被引:1,自引:0,他引:1
A new cavity for diode side-pumped solid-state lasers was designed, built, and tested. The results were efficient absorption of pumped light in the media and homogeneous pumped-beam distribution under various pump-power levels, which generated Nd:YAG active media of different radii and concentrations and shifts of the diode wavelength. Full-multimode quasi-continuous pump operation with a slope efficiency of 40.5% was obtained from a plane-plane resonator equipped with two Nd:YAG rods. At a maximum average pump power of 1.33 kW, the optical-to-optical efficiency was 31.4%. Single-transverse-mode operation (M(2) factor of less than 1.1) of 163 W was demonstrated. 相似文献
95.
96.
Jaroslav Stejskal Pavel Kratochvíl Josef Urban G. S. Kapur Y. Lakshminarayana 《Polymer International》1993,30(1):81-87
Methyl methacrylate was polymerized in an aqueous medium in the presence of gelatin using potassium persulfate as initiator. The dispersion mode of polymerization, when the monomer is completely miscible with water, was investigated and compared with an emulsion process, which proceeds at higher monomer concentration. Spherical and relatively uniform polymer particles were formed. Macroscopic precipitation of polymer is prevented by combination of the steric stabilization by grafted gelatin and of repulsive electrostatic interactions from the initiator residues attached to the particle surface. Static and dynamic light scattering have been used to determine the molar mass (molar mass of the whole dispersion particle, MwD ~ 108-109 g mol?1) and hydrodynamic radius (RhD ~ 50-120 nm) of the particles. The number of particles per unit volume does not depend on overall monomer concentration, and it is higher, and therefore the particle size is smaller, than that observed for the soapless emulsion polymerization. The addition of gelatin may be thus used to modify the particle size. Acrylonitrile dispersions were prepared under similar conditions. Unlike methyl methacrylate, this monomer does not swell the polymer particles. While poly(methyl methacrylate) particles are spherical and relatively uniform, the polyacrylonitrile dispersions consist of polydisperse aggregates of tiny polymer particles. 相似文献
97.
Gérard Demazeau Bernard Buffat Francis Ménil Léopold Fournès Michel Pouchard Jean Michel Dance Pavel Fabritchnyi Paul Hagenmuller 《Materials Research Bulletin》1981,16(11):1465-1472
On the basis of a discussion of the correlations between the stability of the d3 configuration and the symmetry and size of the cation site, six-coordinated iron (V) has been stabilized in the La2LiFeO6 perovskite-type oxide and characterized by magnetic susceptibility, Mössbauer resonance and EPR measurements. 相似文献
98.
New theoretical and practical results concerning the use of discriminant analysis for feature selection are presented in the paper. Numerical values for the eigenvalues of the matrix SWW−1 SB (within-class and between-class scatter matrices) are investigated. An analytic expression for their minimum value representing the minimum effectiveness is derived. Differences between real values and these minimum values are important for the evaluation of the effectiveness of features and thus for feature selection. 相似文献
99.
Somol P Pudil P Kittler J 《IEEE transactions on pattern analysis and machine intelligence》2004,26(7):900-912
A novel search principle for optimal feature subset selection using the Branch & Bound method is introduced. Thanks to a simple mechanism for predicting criterion values, a considerable amount of time can be saved by avoiding many slow criterion evaluations. We propose two implementations of the proposed prediction mechanism that are suitable for use with nonrecursive and recursive criterion forms, respectively. Both algorithms find the optimum usually several times faster than any other known Branch & Bound algorithm. As the algorithm computational efficiency is crucial, due to the exponential nature of the search problem, we also investigate other factors that affect the search performance of all Branch & Bound algorithms. Using a set of synthetic criteria, we show that the speed of the Branch & Bound algorithms strongly depends on the diversity among features, feature stability with respect to different subsets, and criterion function dependence on feature set size. We identify the scenarios where the search is accelerated the most dramatically (finish in linear time), as well as the worst conditions. We verify our conclusions experimentally on three real data sets using traditional probabilistic distance criteria. 相似文献
100.