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排序方式: 共有2723条查询结果,搜索用时 15 毫秒
41.
Abstract— Coatings of indium tin oxide (ITO) nanoparticles on different flexible polymer substrates were investigated with respect to the achievable sheet resistance and their electrical behavior under oscillatory bending. As substrate materials, polyethyleneterephthalate (PET), polyethylenenaphthalate (PEN), polyetheretherketone (PEEK), and polyimide (PI) were chosen, the surface resistances on the different polymer substrates were compared as a function of annealing temperature and surface topography. The surface topography, which has a strong influence on the surface resistance, was characterized by means of a white‐light confocal (WL‐CF) microscope. On the PET substrate, which exhibits the smoothest surface, the coating of ITO nanoparticles shows the lowest sheet resistance of 2 kΩ/□ for a layer thickness of 3 μm and an annealing temperature of 200°C. Furthermore, the electrical behavior of coatings of ITO nanoparticles under oscillatory bending was investigated using a special device. These coatings show a cyclic change of the conductivity which can be explained by an alternating compression and extension of crack flanks under the applied stress. Due to the growing number of cracks with increasing number of cycles, a decrease of the conductivity is observed in the bent state as well as in the balanced state. For a small bending radii, the decrease of the conductivity is stronger due to more cracks caused by the higher tensile stresses in the layer. The electrical behavior of the coatings of the annealed ITO nanoparticles on PET films under oscillatory bending was compared with commercially available sputtered ITO coatings. The annealed coatings of ITO nanoparticles demonstrate better electrical properties under oscillatory bending than coatings of sputtered ITO. The different electrical behavior under oscillatory bending can be related to differences in crack formation. 相似文献
42.
Jan Birnstock Tobias Canzler Michael Hofmann Andrea Lux Sven Murano Philipp Wellmann Ansgar Werner 《Journal of the Society for Information Display》2008,16(2):221-229
Abstract— Currently, three issues are identified that decide upon the commercial success of organic light‐emitting diodes (OLEDs), both in display and lighting applications: power efficiency, lifetime, and price competitiveness. PIN OLEDs are widely seen as the preferred way to maximize power efficiency. Here, it is reported that this concept also delivers the world longest lifetimes. For a highly efficient deep‐red PIN OLED, a half‐lifetime of 25,000 hours for a starting brightness of 10,000 cd/m2 and a minimal voltage increase over lifetime is reported. This value corresponds to more than 1 × 106 hours at 1000 cd/m2 using an exponent of n = 1.7, which was measured by driving the OLEDs at different starting luminances. Because there is no initial luminance drop, these PIN OLEDs also exhibit a very high 80% lifetime (>300,000 hours at 1000 cd/m2). New record lifetime values for blue and green will be reported as well. Additionally, further topics that have impact on the production yield and cost such as the newly developed air‐stable organic n‐doping material NDN‐26 and top‐emitting structures will be discussed. 相似文献
43.
Tobias Storch 《Genetic Programming and Evolvable Machines》2006,7(2):171-193
Different objective functions characterize different problems. However, certain fitness transformations can lead to easier problems although they are still a model of the considered problem. In this article, the class of not worsening transformations for a simple population-based evolutionary algorithm (EA) is described completely. That is the class of functions that transfers easy problems in easy ones and difficult problems in difficult ones. Surprisingly, this class for the rank-based EA equals that for all black-box algorithms. The importance of the black-box algorithms' knowledge of the transformation is also pointed out. Hence, a comparison with the class of not worsening transformations for a similar EA which applies fitness-proportional selection, shows that is a proper superset of . Moreover, is a proper subset of the corresponding class for random search. Finally, the minimal and maximal classes of not worsening transformations are described completely, too. 相似文献
44.
Microstructure Development of Oxycarbide Composites during Active-Filler-Controlled Polymer Pyrolysis 总被引:2,自引:0,他引:2
Tobias Erny Michael Seibold Otto Jarchow Peter Greil 《Journal of the American Ceramic Society》1993,76(1):207-213
The microstructure development of a ceramic composite material fabricated by active-filler-controlled polymer pyrolysis (AFCOP) was investigated. During heating of a polysiloxane precursor mixed with titanium powder in argon atmosphere up to 1400°C, thermally induced decomposition of the polymer phase is combined with simultaneous carburization of the transition metal filler. Precipitation of nanocrystalline titanium carbide at the filler particle surface starts above 400°C, and larger, faceted carbide particles have growth above 800°C. A skeleton of turbostratic carbon is formed above 800°C in the polymer-derived silicon oxycarbide matrix from which b-silicon carbide and cristobalite crystallize above 1000°C. A pronounced reduction in linear shrinkage involved in polymer–ceramic conversion is observed. The shrinkage reduction ranges from more than 25% for the filler-free precursor to less than 10% in the presence of 30 vol% of the titanium filler. Thus, active-filler-controlled pyrolysis offers the possibility of controlling shrinkage and porosity formation during polymer–ceramic conversion in order to fabricate bulk components from organometallic polymer precursor systems. 相似文献
45.
The design of two custom sample holders with a spherical cavity for commercial vibrating sample magnetometer systems is described. For such cavities, the magnetization M[over ->] and the internal magnetic field H(i)[over ->] of a sample are both homogeneous. Consequently, the material parameter M(H(i)) of a sample can be determined even for liquids and powders with a high magnetic susceptibility. 相似文献
46.
47.
Daniel Scherzer Chuong H. Nguyen Tobias Ritschel Hans‐Peter Seidel 《Computer Graphics Forum》2012,31(4):1391-1397
The incident indirect light over a range of image pixels is often coherent. Two common approaches to exploit this inter‐pixel coherence to improve rendering performance are Irradiance Caching and Radiance Caching. Both compute incident indirect light only for a small subset of pixels (the cache), and later interpolate between pixels. Irradiance Caching uses scalar values that can be interpolated efficiently, but cannot account for shading variations caused by normal and reflectance variation between cache items. Radiance Caching maintains directional information, e.g., to allow highlights between cache items, but at the cost of storing and evaluating a Spherical Harmonics (SH) function per pixel. The arithmetic and bandwidth cost for this evaluation is linear in the number of coefficients and can be substantial. In this paper, we propose a method to replace it by an efficient per‐cache item pre‐filtering based on MIP maps — such as previously done for environment maps — leading to a single constant‐time lookup per pixel. Additionally, per‐cache item geometry statistics stored in distance‐MIP maps are used to improve the quality of each pixel's lookup. Our approximate interactive global illumination approach is an order of magnitude faster than Radiance Caching with Phong BRDFs and can be combined with Monte Carlo‐raytracing, Point‐based Global Illumination or Instant Radiosity. 相似文献
48.
This article presents a case study on retrospective verification of the Linux Virtual File System (VFS), which is aimed at
checking violations of API usage rules and memory properties. Since VFS maintains dynamic data structures and is written in
a mixture of C and inlined assembly, modern software model checkers cannot be applied. Our case study centres around our novel
automated software verification tool, the SOCA Verifier, which symbolically executes and analyses compiled code. We describe
how this verifier deals with complex features such as memory access, pointer aliasing and computed jumps in the VFS implementation,
while reducing manual modelling to a minimum. Our results show that the SOCA Verifier is capable of analysing the complex
Linux VFS implementation reliably and efficiently, thereby going beyond traditional testing tools and into niches that current
software model checkers do not reach. This testifies to the SOCA Verifier’s suitability as an effective and efficient bug-finding
tool during the development of operating system components. 相似文献
49.
Andreas L?cken Tobias Hesselmann Martin Pielot Niels Henze Susanne Boll 《Multimedia Systems》2012,18(1):15-31
Music is a fundamental part of most cultures. Controlling music playback has commonly been used to demonstrate new interaction
techniques and algorithms. In particular, controlling music playback has been used to demonstrate and evaluate gesture recognition
algorithms. Previous work, however, used gestures that have been defined based on intuition, the developers’ preferences,
and the respective algorithm’s capabilities. In this paper we propose a refined process for deriving gestures from constant
user feedback. Using this process every result and design decision is validated in the subsequent step of the process. Therefore,
comprehensive feedback can be collected from each of the conducted user studies. Along the process we develop a set of free-hand
gestures for controlling music playback. The situational context is analysed to shape the usage scenario and derive an initial
set of necessary functions. In a successive user study the set of functions is validated and proposals for gestures are collected
from participants for each function. Two gesture sets containing static and dynamic gestures are derived and analysed in a
comparative evaluation. The comparative evaluation shows the suitability of the identified gestures and allows further refinement.
Our results indicate that the proposed process, that includes validation of each design decision, improves the final results.
By using the process to identify gestures for controlling music playback we not only show that the refined process can successfully
be applied, but we also provide a consistent gesture set that can serve as a realistic benchmark for gesture recognition algorithms. 相似文献
50.
We provide a Mathematica code for decomposing strongly correlated quantum states described by a first-quantized, analytical wave function into many-body Fock states. Within them, the single-particle occupations refer to the subset of Fock–Darwin functions with no nodes. Such states, commonly appearing in two-dimensional systems subjected to gauge fields, were first discussed in the context of quantum Hall physics and are nowadays very relevant in the field of ultracold quantum gases. As important examples, we explicitly apply our decomposition scheme to the prominent Laughlin and Pfaffian states. This allows for easily calculating the overlap between arbitrary states with these highly correlated test states, and thus provides a useful tool to classify correlated quantum systems. Furthermore, we can directly read off the angular momentum distribution of a state from its decomposition. Finally we make use of our code to calculate the normalization factors for Laughlin?s famous quasi-particle/quasi-hole excitations, from which we gain insight into the intriguing fractional behavior of these excitations.Program summaryProgram title: StrongdecoCatalogue identifier: AELA_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AELA_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 5475No. of bytes in distributed program, including test data, etc.: 31 071Distribution format: tar.gzProgramming language: MathematicaComputer: Any computer on which Mathematica can be installedOperating system: Linux, Windows, MacClassification: 2.9Nature of problem: Analysis of strongly correlated quantum states.Solution method: The program makes use of the tools developed in Mathematica to deal with multivariate polynomials to decompose analytical strongly correlated states of bosons and fermions into a standard many-body basis. Operations with polynomials, determinants and permanents are the basic tools.Running time: The distributed notebook takes a couple of minutes to run. 相似文献