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261.
Arden L. Bement 《Metallurgical and Materials Transactions B》1987,18(1):5-17
The field of materials science and engineering is advancing at a revolutionary pace. It is now generally recognized as being
among the key emerging technological fields propelling our world societies into the twenty-first century. The driving forces
for this revolutionary pace are at once social, economic, political, and technological. For example, relatively recent changes
in United States federal policies in environmental control, hazardous waste management, and energy conservation along with
heightened international trade competition have resulted in major changes in material processing and use patterns. These changing
patterns are creating new requirements for material developments, substitutions, and associated processes. This paper traces
the emergence of materials policy and technological developments through four sub-periods of history: the birth and development
of engineering in the United States (1825–1900), the evolution of a national research infrastructure (1900–1945), the evolution
of a national science policy (1945–1973), and the intensification of global interdependency (1973-present). Future trends
in materials developments and future policy requirements are outlined.
Technical Resources, of TRW, Inc., began his professional career in 1954 as a research metallurgist and reactor project engineer
with General Electric Co. at the Hanford Atomic Products Operation in Richland, WA. In 1965 he joined Battelle Memorial Institute
as a manager of the metallurgy research department and three years later became manager of the fuels and materials department.
In 1970 Dr. Bement joined the faculty of Massachusetts Institute of Technology as professor of nuclear materials. From 1974
to 1976 he served as a member of the U.S.-U.S.S.R. Bilateral Exchange Program in Magnetohydrodynamics and was the organizer
and principal investigator of the M.I.T. Fusion Technology Program. In 1976 Dr. Bement became Director of the Materials Sciences
Office of the Defense Advanced Research Projects Agency and in 1979 was appointed Deputy Under-Secretary of Defense for Research
and Engineering. Dr. Bement has co-authored one book, edited three books, and authored over 90 articles on materials science,
energy, and defense technology. He is a Fellow of the American Nuclear Society, the American Society for Metals, and the American
Institute of Chemists. In addition, he is a member of the American Institute for Mining, Metallurgical and Petroleum Engineers,
and the American Society for Testing and Materials. He has received outstanding achievement awards from the Colorado Engineering
Council in 1954, the Defense Advanced Research Projects Agency in 1977, and the Colorado School of Mines in 1984. In 1980
he was awarded the Distinguished Civilian Service Medal by the Secretary of Defense. He is a member of the National Academy
of Engineering. Dr. Bement is chairman of the National Materials Advisory Board and a member of the Board of Army Science
and Technology, the Board on Engineering Sciences, the Board on Assessment of National Bureau of Standards Programs, and the
Board on Science and Technology for International Development of the National Research Council. Dr. Bement received an Engineer
of Metallurgy (E. Met.) degree in 1954 from the Colorado School of Mines. He received an M.S. in Metallurgical Engineering
from the University of Idaho in 1959, and a Ph.D. from the University of Michigan in 1963. He is a Lt. Colonel (ret.) in the
U.S. Army Corps of Engineers. Dr. Bement and his family reside in Mayfield Village, OH. 相似文献
262.
We consider three types of near-boundary elements: curvilinear quadrangles and families of arcs and points, and their application to a two-dimensional problem of the static theory of elasticity with boundary conditions in displacements. The comparison of the theoretical and numerical aspects of the obtained solutions is performed. It is shown that the accuracy of evaluation of the components of the vector of displacements increases in the following cases: in the case of complete quantization of the near-boundary region (but not in the case of its partial quantization or quantization with overlapping), in the case where the numbers of arcs and points increase, and in the case of simultaneous application of different types of near-boundary elements (specifically, quadrangles and families of arcs). 相似文献
263.
D. C. Peets R. Liang C. Stock W. J. L. Buyers Z. Tun L. Taillefer R. J. Birgeneau D. A. Bonn W. N. Hardy 《Journal of Superconductivity and Novel Magnetism》2002,15(6):531-534
We have grown cubic centimeter-size crystals of YBa2Cu3O x suitable for neutron studies, by a top-seeded melt-growth technique. Growth conditions were optimized with an eye toward maximizing phase purity. It was found that the addition of 2% Y2BaCuO5 and 0.5% Pt (by mass) were required to prevent melt loss and to obtain the highest crystallinity. A neutron diffraction study on a mosaic of six such crystals found that the final Y2BaCuO5 concentration was 5%, while other impurity phases comprised less than 1% by volume. The oxygen content was set to x = 6.5, the crystals were detwinned, and then carefully annealed to give the well-ordered ortho-II phase. The neutron study determined that 70% of the mosaic's volume was in the majority orthorhomic domain. The neutron (006) and (110) rocking curve widths were ~1° per crystal and ~2.2° for the mosaic, and the oxygen chain correlation lengths were >100 Å in the a- and b-directions and ~50 Å in the c-direction. 相似文献
264.
L A Geddes 《IEEE engineering in medicine and biology magazine》2002,21(3):102-103
Poiseuille, known for his law of fluid flow, which is the analog of Ohm's law, introduced the units (mmHg) by which we measure blood pressure by using the mercury manometer, which he described in his medical school thesis in 1828. For 50 years, mean blood pressure was all that could be measured because of the long response time of the mercury manometer. It is true that the height of the mercury column displayed pulsatile oscillations, but their amplitude was much less than that of pulse pressure. It is interesting to note that the slowly responding mercury manometer was made to display first systolic then diastolic pressure by means of an ingenious device that contained two oppositely directed check valves. It took from 1828 to 1903 for high-fidelity graphic recordings of blood pressure to appear in which systolic and diastolic pressures were believable. However, systolic and diastolic pressures were measurable since 1878 when Golz and Gaule created their ingenious valved device that permitted use of the slowly responding mercury manometer to display these pressures accurately 相似文献
265.
Qin‐Tao Liu Malcolm R Clench Judith L Kinderlerer 《Journal of the science of food and agriculture》2002,82(5):553-558
Structural isomers of monoacylglycerols (monoglycerides, MAGs) were identified and compared after degradation of butter oil by two strains of Penicillium roquefortii and a commercial lipase from P roquefortii (EC 3.1.1.3) at pH 7.0 and 10 °C. The conditions were selected as they were comparable with those used in the manufacture of blue mould‐ripened cheese. The commercial lipase was selected to compare with the fungal strains in terms of acyl migration. Results showed that the main isomers formed by lipolysis with the commercial lipase were sn‐2 MAGs (64 mol%), whilst spores and emerging mycelia of P roquefortii produced mainly sn‐1(3) MAGs (83–90 mol%). The work reported here may lead to further assessment of different MAG structural isomers as natural preservatives in foods and dairy products. © 2002 Society of Chemical Industry 相似文献
266.
巴西的一个重要电力公司COPEL最近开发了一个水电站高级控制系统,这是在电力部门经受重大变革时期,提高水电竞争力的里程碑。 相似文献
267.
Intelligent Monitoring for Adaptation in Grid Applications 总被引:1,自引:0,他引:1
Reed D.A. Mendes C.L. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2005,93(2):426-435
Grid applications access distributed, and often shared, resources. One consequence of this resource sharing is that measured application performance can vary widely and in unexpected ways. Determining the causes of poor performance, due to either anomalous application behavior or contention for shared resource use, and adapting to changing circumstances are critical to creation of robust Grid applications. Performance contracts and real-time adaptive control are two mechanisms to realize soft performance guarantees in Grid environments. Performance contracts formalize the relationship between application performance needs and resource capabilities. During execution, contract monitors use performance data to verify that expectations are met. When the contracted specifications are not satisfied, the system can choose to either adapt the application to available resources or reschedule the application on a new set of resources that can satisfy the original contract specifications. We describe an infrastructure for Grid application contract development and monitoring. This infrastructure, based on the Autopilot toolkit, provides flexible and scalable tools to assess both application and system behavior. 相似文献
268.
269.
A theory is presented that explains how the visual system infers the lightness, opacity, and depth of surfaces from stereoscopic images. It is shown that the polarity and magnitude of image contrast play distinct roles in surface perception, which can be captured by 2 principles of perceptual inference. First, a contrast depth asymmetry principle articulates how the visual system computes the ordinal depth and lightness relationships from the polarity of local, binocularly matched image contrast. Second, a global transmittance anchoring principle expresses how variations in contrast magnitudes are used to infer the presence of transparent surfaces. It is argued that these principles provide a unified explanation of how the visual system computes the 3-D surface structure of opaque and transparent surfaces. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
270.
Serran G.; Fernandez Y.; Marshall W. L.; Mann R. E. 《Canadian Metallurgical Quarterly》2003,34(4):368
How critical is the therapeutic alliance in the treatment of sexual offenders? To date such process issues have been neglected in the field of sex offender treatment. This article reviews the literature on the influence on behavior change of therapist features, clients' perceptions, and the therapeutic alliance. Among the many therapist features identified as helpful are empathy, warmth, and being directive and rewarding. Therapists who are aggressively confrontational appear not to foster beneficial changes in their clients. These issues are directly related to treatment issues faced by therapists who work with sexual offenders, such as dealing with cognitive distortions, lack of empathy, and lack of motivation to change. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献