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91.
A learning event can be dissociated into 3 components: acquisition, storage, and recall. When the laboratory wild-type strain of Caenorhabditis elegans (N2 strain) is exposed to benzaldehyde in the absence of food, the worms display a reduction of their attractive response to this volatile odorant. This results from the association between benzaldehyde and a nutrient-deficient environment. Another wild-type isolate, the CB4856 strain, fails to display this decreased response to benzaldehyde after exposure to benzaldehyde in the absence of food. However, like the N2 strain, when tested to isoamyl alcohol after benzaldehyde conditioning, the CB4856 strain displays a decreased isoamyl alcohol response. Therefore, the CB4856 strain does not have an acquisition deficit, but it suffers from a recall deficit specific to benzaldehyde. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
92.
Existing NASA supported scientific databases are usually developed and managed by a team of database administrators whose main concern is the efficiency of the databases in terms of normalization and data search constructs. The populating of the database is usually done in a manual fashion by row and column as the data become available, and the data dictionary is usually defined by the same team (at times with little input from the end science user). This process is tedious, error prone and self-limiting in terms of what can be described in a relational Data Base Management System (DBMS). The next generation Earth remote sensing platforms [i.e., Earth Observing System (EOS)] will be capable of generating data at a rate of over 300 Megabits per second from a suite of instruments designed for different applications. What is needed is an innovative approach that creates object-oriented data-bases that segment, characterize, and catalog, and are manageable in a domain-specific context, and whose contents are available interactively and in near-real-time to the user community. This paper describes work in progress that utilizes an artificial neural net approach to characterize satellite imagery of undefined objects into high-level data objects. The characterized data is then dynamically allocated to an object-oriented database where it can be reviewed and accessed by a user. The definition, development, and evolution of the overall data system model are steps in the creation of an application-driven knowledge-based scientific information system.  相似文献   
93.
Since Feynman’s 1959 lecture, “There’s Plenty of Room at the Bottom,” and particularly in the last 15 years, advances in instrumentation have permitted us to observe and characterize materials at atomic scale. New and even more powerful capabilities are rapidly becoming available. At the same time, our theoretical understanding and ability to model complex systems have matured to a level that enables us to begin making useful predictions in many areas, with the promise of further progress as we approach petascale computing. Progress in making and structuring nanoscale materials in commercially useful quantities is also being made, albeit more selectively. Exploiting chemistry and biochemistry to mimic nature’s accomplishments in living systems is a promising approach that is opening new possibilities. The remarkable progress of the last few years is already producing technological advances, and more can be expected as investments in nanoscience and nanotechnology increase. Just as advances in information technology during the second half of the 20th century produced dramatic technological, economic, and societal changes, so the coming nanoscale revolution will affect virtually every aspect of life in the 21st century. with Erik W. Pearson Since 1975, Dr. Madia has been a leader in research and research management at Battelle. His extensive experience in setting organizational vision, maximizing research output, and building complex teams has served Battelle and the nation for more than three decades. Dr. Madia currently leads Battelle’s Laboratory Operations business, where he oversees the management or co-management of five U.S. Department of Energy national laboratories: Pacific Northwest National Laboratory, Brookhaven National Laboratory, National Renewable Energy Laboratory, Oak Ridge National Laboratory, and Idaho National Laboratory. His portfolio includes Battelle’s Strategic Project Management business and various lab-based commercialization initiatives. Previously, he spearheaded the strategy and execution of Battelle/University of Tennessee (UT)’s winning bid to operate the Oak Ridge National Laboratory. Here, he also served as Director, ORNL, the largest multiprogram national laboratory with 3800 staff and research revenues exceeding $1 billion. In addition to completing the $1.4 billion Spallation Neutron Source project, his agenda for ORNL was shaped by a commitment to achieve simultaneous excellence in the areas of science and technology, laboratory operations, and community service. Dr. Madia’s widely recognized leadership at ORNL was strengthened from his tenure as Director of the Pacific Northwest National Laboratory (PNNL) in Richland, WA. From 1994 to 1999, he focused PNNL’s mission on environmental science and technology, launched a $60 million cost reduction and productivity program, and oversaw the construction of the Environmental Molecular Sciences Laboratory—the first major DOE scientific user facility built on PNNL’s campus. Before leading the national laboratories at Richland and Oak Ridge, Dr. Madia managed Battelle’s global environmental business, overseeing an $800 million portfolio that included developing environmental restoration and waste management technologies, along with environmental systems and planning. Earlier, as president of Battelle Technology International, he led Battelle’s research, development, and applications efforts involving more than 4100 scientists, engineers, and support personnel at major laboratory facilities in Columbus, OH; Frankfurt, Germany; and Geneva, Switzerland. Dr. Madia also served as director of Battelle’s Columbus Laboratories, managing a staff of 3200. In each of these positions, he concentrated on moving science and technology out of the laboratory and into commercial applications. Prior to these assignments, he was corporate vice president and general manager of Battelle’s Project Management Division, where he managed Battelle’s Systems Engineering business. Throughout his career, Dr. Madia has earned many awards and honors, including the Secretary of Energy’s Gold Award and DOE’s Distinguished Associate Award. He was named “Laboratory Director of the Year” in 1999 by the Federal Laboratory Consortium and was nominated for the National Medal of Technology. He also received the Sigma Xi Research Award in Chemistry from the Virginia Polytechnic Institute and a U.S. Army Commendation Medal for nuclear engineering while serving in the military. Dr. Madia is the author of numerous journal articles in the fields of radiochemistry and quantum mechanics as well as technical reports and publications in the field of nuclear technology. He holds bachelor’s and master’s degrees in chemistry from the Indiana University of Pennsylvania, where he is a “Distinguished Alumnus.” He earned a Ph.D. in chemistry from the Virginia Polytechnic Institute. He serves on numerous civic, charitable, and corporate boards. He and his wife Audrey have three sons.  相似文献   
94.
Models and methods are presented for determining practical limits of the packing density of TRISO particles in fuel pebbles for a pebble-bed reactor (PBR). These models are devised for designing and interpreting fuel testing experiments. Two processes for particle failure are accounted for: failure of touching particles at the pressing stage in the pebble manufacturing process and failure due to inner pressure buildup during irradiation. The second process gains importance with increasing fuel temperature, which limits the particle packing density and the corresponding fuel enrichment. Suggestions for improvements to the models are presented.  相似文献   
95.
Earlier studies conducted in the use of sealed tubes with polyalkylene glycol lubricants and polyethylene terephthalete (PET) films revealed that the PET films exhibited embrittlement and (visual) degradation. This led to an investigation of PET embrittlement mechanisms with the new lubricants used with HFC 134a. The lubricants studied were three polypropylene glycols (the monol, the diol and the completely end-capped glycols), pentaerythritol ester and a blend of monol and ester. The effects of moisture content, temperature and lubricant structure were studied. All lubricants in this study were of viscosity grade ISO-32 (150 SUS). The results were compared to PET film embrittlement in the presence of CFC 12 and mineral oil. This study reconfirmed the earlier findings that the PET films must be dried to lower than 0.1 wt.% moisture content for use in hermetic systems. This paper discusses the effect of the moisture content of the lubricant and the effect of the lubricant structure on PET films. The dependence of the various mechanisms on temperature is shown. Esters and end-capped polyalkylene glycols are recommended for use with HFC 134a.  相似文献   
96.
Starches isolated from 23 bread wheats (Triticum aestivum) and 26 durum wheats (T. durum) contained 26.3-30.6% (mean 29.1%) total amylose, 19.3–25.1% (mean 22.9%) apparent amylose and 783–1144mg 100g?1 (mean 977 mg 100g?1) lysophos-pholipids. Gelatinisation temperatures were 57.3–64.9°C (mean 61.8°C) and enthalpies 6.4–11.8 Jg?1 (mean 9.7Jg?1) in excess water, measured by differential scanning calorimetry. There were no correlations between any of these parameters. Starch granule size distributions were determined with a Coulter Counter and 100–channel analyser. A-granule mean volumes were 1235–2585μm3 (av. 1778), modal volumes 863–1804μm3 (av. 1264), mean diameters 13.9–16.0μm (av. 13.99), and specific surface areas 0.236–0.302m2g?1. B-granule mean volumes were 35.4–100.4μm3 (av. 55.9), modal volumes 16.5–54.5μm3 (av. 27.7), mean diameters 3.66–5.07μm (av. 4.09), and specific surface areas 0.684–0.920m2g?1. The B-granule contents of the starches were 12.8–34.6% (av. 27.3) by weight (sedimentation method) and 13.0–37.3% (av. 24.0) by volume (Coulter method), the latter being the more accurate method.  相似文献   
97.
Vipin K. Garg  William R. Nes 《Lipids》1985,20(12):876-883
While seeds ofCucurbita maxima contain both Δ5- and Δ7-sterols, the former, which have been described earlier, now have been found to disappear during germination. This suggests that a function exists for the Δ5-compounds only in the early part of the life cycle ofC. maxima, unlike most of the other higher plants studied. In contrast to the Δ5-sterols, the level of Δ7-sterols increased during germination as well as during seedling development and maturation. The period of transition between germination and seedling development appeared to be of special importance in terms of sterol changes. This period represented a surge of sterol biosynthesis with an ontogenetic shift in sterol composition from approximately equal amounts of 24α- and 24β-ethyl stereochemistry to a predominance of the former. The sterol composition of the mature plants included only about 5% of the 24β-ethylsterols. The configurational relationships were demonstrated by high resolution1H-NMR. The sterols of the mature plants were: 25(27)-dehydrochondrillasterol, 24β-ethyl-25(27)-dehydrolathosterol, avenasterol, spinasterol, 22-dihydrospinasterol and 24ξ-methyllathosterol. Based on the changes which occurred in the relative amounts of the Δ7-sterols, it did not appear that the Δ5-components were being converted to their Δ7-analogs. A portion of this work was presented at the meeting of the American Oil Chemists' Society in May, 1985 in Philadelphia.  相似文献   
98.
This article describes a non-contact method for measuring surface velocity and discharge in a natural channel. The X-band pulse (9.36 GHz) radar, developed by the Applied Physics Laboratory of the University of Washington, was used to scan instantaneously the lateral distribution of surface velocity across a river section, according to Bragg scattering from short waves produced by turbulent boils on the surface of the river. Based on the assumption that the vertical velocity distribution follows a universal power or logarithmic law, the discharges were estimated.  相似文献   
99.
A framework for incorporating uncertainty in risk management is developed and applied to two aspects of decision making: meeting standards or safety goals, and cost-benefit criteria. The framework is applied to several case studies including toxic chemicals in water, failure of civil engineering structures and nuclear power plants. The framework proposes that decisions be based on a level of confidence, in addition to comparing best estimate or point values with standards and goals.  相似文献   
100.
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