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71.
72.
Extending the Unified Modeling Language for ontology development 总被引:3,自引:0,他引:3
Kenneth Baclawski Mieczyslaw K. Kokar Paul A. Kogut Lewis Hart Jeffrey Smith Jerzy Letkowski Pat Emery 《Software and Systems Modeling》2002,1(2):142-156
There is rapidly growing momentum for web enabled agents that reason about and dynamically integrate the appropriate knowledge
and services at run-time. The dynamic integration of knowledge and services depends on the existence of explicit declarative
semantic models (ontologies). We have been building tools for ontology development based on the Unified Modeling Language
(UML). This allows the many mature UML tools, models and expertise to be applied to knowledge representation systems, not
only for visualizing complex ontologies but also for managing the ontology development process. UML has many features, such
as profiles, global modularity and extension mechanisms that are not generally available in most ontology languages. However,
ontology languages have some features that UML does not support. Our paper identifies the similarities and differences (with
examples) between UML and the ontology languages RDF and DAML+OIL. To reconcile these differences, we propose a modification
to the UML metamodel to address some of the most problematic differences. One of these is the ontological concept variously
called a property, relation or predicate. This notion corresponds to the UML concepts of association and attribute. In ontology
languages properties are first-class modeling elements, but UML associations and attributes are not first-class. Our proposal
is backward-compatible with existing UML models while enhancing its viability for ontology modeling. While we have focused
on RDF and DAML+OIL in our research and development activities, the same issues apply to many of the knowledge representation
languages. This is especially the case for semantic network and concept graph approaches to knowledge representations.
Initial sbmission: 16 February 2002 / Revised submission: 15 October 2002 Published online: 2 December 2002 相似文献
73.
We present a system for generating suggestions from highly‐constrained, continuous design spaces. We formulate suggestion as sampling from a probability distribution; constraints are represented as factors that concentrate probability mass around sub‐manifolds of the design space. These sampling problems are intractable using typical random walk MCMC techniques, so we adopt Hamiltonian Monte Carlo (HMC), a gradient‐based MCMC method. We implement HMC in a high‐performance probabilistic programming language, and we evaluate its ability to efficiently generate suggestions for two different, highly‐constrained example applications: vector art coloring and designing stable stacking structures. 相似文献
74.
Rheological properties of toluene solutions of nitrile butadiene rubber, of different molecular weights (Mw, 290,000,320,000, and 450,000) and acrylonitrile contents (30 and 40 percent), were investigated at low (0.1 S?1) to medium (20,0 S?1) shear rates, in order to determine their feasibility for dip-coating applications. The effect of a surface-active additive, bentonite, and the solid content (15 and 20 wt percent) on solution viscosity was of main interest. At low zero-shear viscosity (<50 Pa·S) an excessive sagging of the wet film was experienced; at high zeroshear viscosity (>100 Pa-·S) the coating showed poor leveling. Zeroshear viscosity was found to be less affected by bentonite than oligomer-based solutions, at the same time, the solid content and the molecular weight of the polymer had more pronounced effects. With a proper balance of the parameters, seamless coating films were achieved, with excellent tensile and tear properties, and good permeation resistance against benzene. 相似文献
75.
Algorithms for determining quality/cost/price tradeoffs in saturated markets are considered. A product is modeled by d real-valued qualities whose sum determines the unit cost of producing the product. This leads to the following optimization
problem: given a set of n customers, each of whom has certain minimum quality requirements and a maximum price they are willing to pay, design a new
product and select a price for that product in order to maximize the resulting profit. 相似文献
76.
Morawski Birgit; Lin Zhanglin; Cirino Pat; Joo Hyun; Bandara Geethani; Arnold Frances H. 《Protein engineering, design & selection : PEDS》2000,13(5):377-384
The ability to engineer proteins by directed evolution requiresfunctional expression of the target polypeptide in a recombinanthost suitable for construction and screening libraries of enzymevariants. Bacteria and yeast are preferred, but eukaryotic proteinsoften fail to express in active form in these cells. We haveattempted to resolve this problem by identifying mutations inthe target gene that facilitate its functional expression ina given recombinant host. Here we examined expression of HRPin Saccharomyces cerevisiae. Through three rounds of directedevolution by random point mutagenesis and screening, we obtaineda 40-fold increase in total HRP activity in the S.cerevisiaeculture supernatant compared with wild-type, as measured onABTS [2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)](260 units/l/OD600). Genes from wild-type and two high-activityclones were expressed in Pichia pastoris, where the total ABTSactivity reached 600 units/l/OD600 in shake flasks. The mutantsshow up to 5.4-fold higher specific activity towards ABTS and2.3-fold higher specific activity towards guaiacol. 相似文献
77.
Tawatchai Charinpanitkul Pat Nartpochananon Thornchaya Satitpitakun Jenifer Wilcox Takafumi Seto Yoshio Otani 《Journal of Industrial and Engineering Chemistry》2012,18(1):469-473
Facile synthesis of tetrapodal ZnO nanoparticles was conducted using a modified French process in which oxygen and nitrogen flow rates were controlled. The synthesized ZnO nanoparticles exhibit photoluminescent characteristics depending on the synthesis conditions. Electron microscopic analysis revealed that the tetrapodal nanostructure of ZnO with high crystallinity which was confirmed by XRD analyses could be controlled by a variation of O2/N2 feed ratio. Typical photoluminescence with UV and blue emission of the tetrapodal ZnO nanoparticles was influenced by the particle size and crystallinity, which is manipulated by the oxidation condition. 相似文献
78.
79.
Usability of many call center IVRs (Interactive Voice Response systems) is dismal. Callers dislike touch-tone IVRs and seek agent assistance at the first opportunity. However, because of high agent costs, call center managers continue to seek automation with IVRs. The challenge for call centers is providing user-friendly, yet cost-efficient, customer service. This article describes a comprehensive methodology for usability re-engineering of telephone voice user interfaces based on detailed call center assessment and call flow redesign. At the core of our methodology is a data-driven IVR assessment, in which we analyze end-to-end recordings of thousands of calls to evaluate IVR cost effectiveness and usability. Because agent time is the major cost driver in call center operations, we quantify cost-effectiveness in terms of agent time saved by automation in the IVR. We identify usability problems by carefully inspecting user-path diagrams, a visual representation of the sequence of events of thousands of calls as they flow through the IVR. Such an IVR assessment leads directly into call-flow redesign. Assessment insights lead to specific suggestions on how to improve a call-flow design. In addition, the assessment enables us to estimate the cost savings of a new design, thus providing the necessary business justification. We illustrate our IVR usability and re-engineering methodology with examples from large commercial call centers, demonstrating how the staged process maximizes the payback for the call center while minimizing risk. 相似文献
80.
Hisashi Yamamoto Yoshio Otani Takafumi Seto Pat Nartpochananon Tawatchai Charinpanitkul 《Advanced Powder Technology》2012,23(1):71-79
Tetrapod-shaped ZnO particles are generated via gas-phase reaction of Zn vapor and oxygen in air, where they undergo homogeneous nucleation from supersaturated ZnO vapor and successive growth by surface reaction. It was found that a simple device for flow restrictor is effective in making ZnO particles of terapod-shape by leaving sufficient amounts of unreacted Zn vapor with the embryos of ZnO. In the absence of the flow restrictor, only spherical particles are formed because the oxidation reaction takes place immediately after mixing and unreacted Zn vapor does not remain for the subsequent crystal growth. The Zn vapor concentration distribution, oxygen concentration distribution, temperature, gas velocity and reaction rate in the reactor were analyzed by using a conventional computational fluid dynamic simulation package. The simulation revealed that the flow restrictor does not enhance mixing between Zn vapor and air but suppresses the mixing and reduces the residence time in the reactor so that sufficient amounts of unreacted Zn vapor remain downstream of the flow restrictor, allowing ZnO particles to grow in tetrapod-shape by abnormal crystal growth. 相似文献