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181.
This paper presents a performance study of a one-dimensional search algorithm for solving general high-dimensional optimization problems. The proposed approach is a hybrid between a line search algorithm of Glover (The 3-2-3, stratified split and nested interval line search algorithms. Research report, OptTek Systems, Boulder, CO, 2010) and an improved variant of a global method of Gardeux et al. (Unidimensional search for solving continuous high-dimensional optimization problems. In: ISDA ’09: Proceedings of the 2009 ninth international conference on intelligent systems design and applications, IEEE Computer Society, Washington, DC, USA, pp 1096–1101, 2009) that uses line search algorithms as subroutines. The resulting algorithm, called EM323, was tested on 19 scalable benchmark functions, with a view to observing how optimization techniques for continuous optimization problems respond with increasing dimension. To this end, we report the algorithm’s performance on the 50, 100, 200, 500 and 1,000-dimension versions of each function. Computational results are given comparing our method with three leading evolutionary algorithms. Statistical analysis discloses that our method outperforms the other methods by a significant margin.  相似文献   
182.
Dynamic friction and static immersion tests in which oil temperature was varied and dynamic friction tests in which load was varied have been run on steel balls with oil blends containing seven commercial additives. Analyses of the ball surfaces by X-ray fluorescence have shown that significant surface coating formation is initiated at calculated surface temperatures of from 250 to 350 F for most of the additives studied. Although the surface coating “thickness” generally increased with temperature, the rate of increase was generally different for the static and dynamic tests. Both surface temperature and mechanical shearing appear to influence the reactions responsible for the surface coatings. Used oil analyses showed that base oil oxidation, additive decomposition, and, in some cases, sludge formation became detectible at temperatures corresponding to the start of significant surface coating formation. The results suggest that in situ polymerization may be an important phenomenon occurring on rubbing surfaces.  相似文献   
183.
This article presents results from a survey of ethical beliefs about practice dilemmas unique to clinical work with children and adolescents. Survey data suggest that identical practices are not always ethically equivalent, particularly when the developmental status of the client is varied. The survey also reveals widespread ambiguity about what constitutes ethical practice, as manifested both in individual uncertainty and in the absence of group consensus. Ethically guided clinical practice is presented as a far more complex undertaking than adherence to a single set of professional standards. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
184.
Abstract— This report outlines a theoretical solution for the estimation of rainflow range density functions using statistics computed directly from power spectral density data. The rainflow range mechanism is broken down into a set of events which can be analyzed using Markov process theory. The dependence between extremes in this instance is modelled using an approximation of the joint distribution of peaks and troughs first proposed by Kowalewski.  相似文献   
185.
E-glass/epoxy-based jackets have been demonstrated to be an effective means of providing lateral confinement for the seismic retrofit and strengthening of concrete columns. When fabricated using appropriate procedures and covered with a protective coating these materials show good environmental durability. However, E-glass fibers are susceptible to attack and degradation by moisture and alkalis, causing concern for their use in humid and very moist climates or in applications where the jacketed columns are immersed in water. This paper describes the enhancement of durability through change in the sizing used on the fibers. Results of ring burst tests on three differently sized systems after immersion in a severe environment [water at 60°C (140°F)] are detailed, and it is shown that the use of the appropriate sizing can significantly reduce moisture-related degradation.  相似文献   
186.
Over the last several years, computing has changed to an almost purely networked environment, but the technical aspects of information protection have not kept up. As a result, the success of information security programmes has increasingly become a function of our ability to make prudent management decisions about organizational activities. These articles take a management view of protection. They seek to reconcile the need for security with the limitations of technology.  相似文献   
187.
张东彦  张卫平  D Y Chen  Fred C Lee 《电子学报》2003,31(11):1648-1650
基于功率流方法,本文提出了一种分析压电陶瓷变压器电气特性的方法.其主要贡献是:(1)给出了计算最佳负载、电压增益、效率和输出功率等电气特性的公式;(2)利用这些公式,给出了分析压电陶瓷变压器电气特性的计算程序,并提出了最佳电阻和最佳匹配网络的概念;(3)为了证明其理论结果,文中给出了仿真结果.本文所得到的结果为分析压电陶瓷变压器电气特性提供了一个有用的工具.  相似文献   
188.
认识电阻、电容、电感及如何选用LCR电桥   总被引:1,自引:0,他引:1  
叶正贤 《电子质量》2003,(3):119-120
在不同频率的电路中,LCR的等效电路、应用以及正确使用LCR电桥测试的方法。  相似文献   
189.
Response of structures to static and dynamic loads may be assessed in terms of energy. The energy evaluation depends on hysteretic models used to describe inelastic behavior of structures and their elements. One of the hysteretic models often employed in structural analysis is the Ramberg–Osgood model. In the paper a physically motivated model, which leads to the Ramberg–Osgood force–displacement relationship under monotonic loading and exhibits Masing type of behavior for unloading/reloading, is described. Based on the model formulas to calculate recoverable elastic strain energy and irrecoverable hysteretic energy for systems/elements under monotonic loading are derived. It is also shown how recoverable elastic strain energy and irrecoverable hysteretic energy can be evaluated at any point of unloading/reloading curves for a system/element of Masing type. The application of the derived formulas is illustrated by evaluating the energy of a single-degree-of-freedom system subjected to impulse and seismic loading.  相似文献   
190.
We have applied scanning transmission electron microscopy to intact native fibrillin-containing microfibrils isolated from foetal bovine elastic tissues in order to derive new insights into microfibril organisation. This technique provides quantitative data on the mass per unit length and axial mass distribution of unstained, unshadowed macromolecules. Scanning transmission electron microscopy of microfibrils from aorta, skin and nuchal ligament revealed that the beads corresponded to peaks of mass and the interbead regions to troughs of mass. These major features of axial mass distribution were characteristic of all microfibrils examined. Tissue-specific and age-dependent variations in mass were identified in microfibrils that were structurally comparable by rotary shadowing electron microscopy. Increased microfibril mass correlated with increasing gestational age. The additional mass was associated predominantly at, or close to, the bead. Some microfibril populations exhibited pronounced assymetry in their axial mass distribution. These data indicate that intact native microfibrillar assemblies from developing elastic tissues are heterogeneous in composition. Loss of mass following chondroitinase ABC or AC lyase treatment confirmed the presence of chondroitin sulphate in nuchal ligament microfibrillar assemblies.  相似文献   
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