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Manufacturing industries are rapidly changing from economies of scale to economies of scope, characterized by short product life cycles and increased product varieties. This implies a need to improve the efficiency of job shops while still maintaining their flexibility. These objectives are achieved by Flexible manufacturing systems (FMS). The basic aim of FMS is to bring together the productivity of flow lines and the flexibility of job shops. This duality of objectives makes the management of an FMS complex. In this article, the loading problem in random type FMS, which is viewed as selecting a subset of jobs from the job pool and allocating them among available machines, is considered. A heuristic based on multi-stage programming approach is proposed to solve this problem. The objective considered is to minimize the system unbalance while satisfying the technological constraints such as availability of machining time and tool slots. The performance of the proposed heuristic is tested on 10 sample problems available in FMS literature and compared with existing solution methods. It has been found that the proposed heuristic gives good results. 相似文献
43.
Mahesh Gupta Nissreen Abu‐Ghannam Eimear Gallaghar 《Comprehensive Reviews in Food Science and Food Safety》2010,9(3):318-328
ABSTRACT: Barley is the basic raw material for brewing. Its chemical composition, brewing, and technological indices are highly determinative for the beer quality and the economical efficiency of the brewing process. Barley is rich in protein, carbohydrates, dietary fibers, minerals, and vitamins. The presence of nonstarch polysaccharides as mixed linkage (1‐3),(1‐4)‐β‐d ‐glucans and arabinoxylans together with the enzymes are responsible for barley modification. Malting is a complex process that involves many enzymes; important ones are α‐amylase, β‐amylase, α‐glucosidase, and limit dextrinase. During the process of malting and brewing, the by‐products left after separation of the wort are rich in protein, fibers, arabinoxylans, and β‐glucan. This review summarizes and integrates barley grain with respect to nutritional, functional, and compositional changes that take place during malting and brewing. It also explores in‐depth the several by‐products obtained after brewing and their potential for various food applications. Barley brewing by‐products offer an opportunity for cereal‐based baked and extruded products with acceptable sensory and nutritional characteristics. 相似文献
44.
Building useful systems with an ability to understand "real" natural language input has long been an elusive goal for Artificial Intelligence. Well-known problems such as ambiguity, indirectness, and incompleteness of natural language inputs have thwarted efforts to build natural language interfaces to intelligent systems. In this article, we report on our work on a model of understanding natural language design specifications of physical devices such as simple electrical circuits. Our system, called KA, solves the classical problems of ambiguity, incompleteness and indirectness by exploiting the knowledge and problem-solving processes in the situation of designing simple physical devices. In addition, KA acquires its knowledge structures (apart from a basic ontology of devices) from the results of its problem-solving processes. Thus, KA can be bootstrapped to understand design specifications and user feedback about new devices using the knowledge structures it acquired from similar devices designed previously.In this paper, we report on three investigations in the KA project. Our first investigation demonstrates that KA can resolve ambiguities in design specifications as well as infer unarticulated requirements using the ontology, the knowledge structures, and the problem-solving processes provided by its design situation. The second investigation shows that KA's problem-solving capabilities help ascertain the relevance of indirect design specifications, and identify unspecified relations between detailed requirements. The third investigation demonstrates the extensibility of KA's theory of natural language understanding by showing that KA can interpret user feedback as well as design requirements. Our results demonstrate that situating language understanding in problem solving, such as device design in KA, provides effective solutions to unresolved problems in natural language processing. 相似文献
45.
The present experimental study characterizes the turbulent LPG Inverse Diffusion Flame (IDF) stabilized in a backstep burner in terms of visible flame length, dual flame structure, centerline temperature distribution, and oxygen concentration. The visible flame length for a fixed fuel jet velocity is found to reduce with increase in air jet velocity. Besides this, the effect of air and fuel jet velocities on visible flame length is interpreted using a new parameter, Global Momentum Ratio (GMR). Interestingly, GMR seems to be correlating well with the visible flame length for the air and fuel velocity ranges considered in the present study. Moreover, the dual flame structure of IDF is identified with the help of CH-chemiluminescence signature. The existence of dual flame structure of IDF is confirmed further with the centerline temperature and oxygen concentration measurements. 相似文献
46.
That computing and communication systems are becoming increasingly interdependent is evident in almost every aspect of society. Applications of these integrated systems are also spreading. As this trend continues, it will force the computing community not only to develop revolutionary systems but also to redefine “computer system” and the roles of traditional research disciplines, such as operating systems, architectures, compilers, languages, and networking. Systems research faces an unprecedented challenge. Systems developers are facing a major discontinuity in the scale and nature of both applications and execution environments. Applications are changing from transforming data to directly interacting with humans; they will use hardware and data that span wide area, even global, networks of resources and involve interactions among users as well. Even the architecture of individual processors is uncertain. The authors look at three challenges facing systems research, describe developing solutions, and review remaining obstacles. Using this information, they formulate three clear first steps to addressing the identified challenges: (a) define a new paradigm for systems research; (b) attack problems common to all system development; (c) build a research infrastructure 相似文献
47.
During the last 20 years, new philosophies such as the Theory of Constraints (TOC) and Activity-Based Management (ABM) have emerged as viable, distinct alternatives for measuring and improving the performance of world-class manufacturing companies. In the early phase of their evolution, these philosophies differed fundamentally in their approaches; but there is increasing evidence that both philosophies have now evolved to a stage where an integrated framework can be developed for enhancing cross-functional coordination, thereby improving organizational performance. In this paper, a general framework is presented that integrates the basic concepts, as well as recent advances of TOC and ABM philosophies, into a cohesive framework that can be used to guide performance improvement initiatives . A successful implementation in a world-class manufacturing company is described to validate the framework and to demonstrate that these philosophies can indeed work together in positive ways. Insights are provided into the reasons for implementing such an integrative framework, e.g. identifying the most profitable mix of products, allocating scarce resources optimally, establishing priorities for process improvements, analysing the strategic investment (or expansion) alternatives, and exploiting new market segments. 相似文献
48.
49.
Chloromethylated styrene-divinylbenzene copolymer was chemically modified with ethylenediaminetetraacetic acid ligand. Catalytically
active polymer containing Ru(III) moieties were synthesized from this polymeric ligand. They were characterized using FTIR,
UV-vis, SEM, ESR and TGA. Other physico-chemical properties such as bulk density, surface area, moisture content and swelling
behaviour in different solvents were also studied. The polymer bound complex was used to study hydrogenation of 1-hexene ton-hexane under mild conditions. Influence of [1-hexene], [catalyst], temperature and nature of the solvent on the rate of the
reaction was investigated. A rate expression is proposed based on the observed initial rate data. Recycling efficiency of
the catalyst has also been studied. 相似文献
50.