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41.
The history of wireless power transmission at microwave frequencies is reviewed with emphasis upon the time period starting with the post World War II efforts to use the new microwave technology developed during the war. A nationally televised demonstration of a microwave powered helicopter at the Spencer Laboratory of the Raytheon Co., in 1964 was the result of these early efforts and broadly introduced the concept of wireless power transmission to scientific and engineering communities and to the public. Subsequent development efforts centered on improving the efficiency of the interconversion of d.c. and microwave power at the ends of the system to reach a demonstrated overall d.c. to d.c. system efficiency of 54% in 1974. The response to the requirements of applications such as the Solar Power Satellite and high altitude microwave powered aircraft have changed the direction of technology development and greatly expanded the technology base. Recent and current efforts are centered on examining the use of higher frequencies than the baseline 2.45 GHz, and in reducing the system costs at 2.45 GHz.  相似文献   
42.
The linear theory of Pearson (1958) and Nield (1964) is modified here to study liquid tin and include the finite thermal resistances of the bounding layers of boron nitride, copper and air (∼10-2 torr) in the experiments of Ginde et al. (1989). The magnitude of the ΔTc across the layer of liquid tin required for the onset of convection depends on the ratios of the thermal conductivities and thicknesses of the supporting layers of boron nitride and copper to those of the tin.

According to our theory surface tension contributes more than buoyancy to the instability observed experimentally. The critical ΔTc observed required for the onset of convection in the layer of tin, is up to 25% lower than that predicted, which shows the layer is less stable than the theory indicates. Thus the surface of the tin was uncontaminated, or a significantly larger observed critical ΔTc would be expected.

The boundary condition on the thermal fluctuations at the base of the supporting layer of copper does not appear to be important in these experiments. However, the thermal resistance of the boron nitride would have to be assumed to be unrealistically large to obtain agreement within experimental error with the theory.  相似文献   
43.
Feedback provided to Ss and 3rd parties from intra- and extramural investigators following the completion of research involving an agency's clients or staff is described. Ss were from the division of a public health department that provides mental health and substance abuse services in a city with 740,000 people. The division's research requirements include submission of annual progress reports and final reports. Of 135 studies conducted over 12 yrs, annual reports were received from 37% of investigators, and final reports from 30%. There were no significant differences based on investigator discipline or affiliation. Professional and ethical implications are discussed, including adequacy of professional training, the need for mechanisms to ensure compliance with ethical standards, the obligations of clinic directors, and the impact on public academic liaison programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
44.
45.
The utilization of explosives for excavation on the lunar surface is under serious consideration as a part of the design for construction of temporary and permanent bases. An excavation research program has shown that small‐scale explosives blasting in a lunar‐soil simulant will greatly reduce the digging forces required for scoop and dragline excavators. Some crater‐blasting parameters were determined for the lunar soil simulant at one Earth gravity and at 10 Earth gravities using a centrifuge. The size of the craters produced at 10 Earth gs matched those formed at one earth g by scaling according to the weight of the explosive. These data can be applied to explosive‐excavation problems such as habitat construction, burial of nuclear power sources, and the rapid construction of shelters remote from the main base to shield against solar‐flare activity.  相似文献   
46.
Experimental tests showed that poststrike elevation in tongue-flicking rate (PETF) and strike-induced chemosensory searching (SICS) in the gila monster last longer than reported for any other lizard. Based on analysis of numbers of tongue-flicks emitted in 5-min intervals, significant PETF was detected in all intervals up to and including minutes 41–45. Using 10-min intervals, PETF lasted though minutes 46–55. Two of eight individuals continued tongue-flicking throughout the 60 min after biting prey, whereas all individuals ceased tongue-flicking in a control condition after minute 35. The apparent presence of PETF lasting at least an hour in some individuals suggests that there may be important individual differences in duration of PETF. PETF and/or SICS are present in all families of autarchoglossan lizards studied except Cordylidae, the only family lacking linguallly mediated prey chemical discrimination. However, its duration is known to be greater than 2-min only in Helodermatidae and Varanidae, the living representatives of Varanoidea. That prolonged PETF and SICS are typical of snakes provides another character supporting a possible a varanoid ancestry for Serpentes. Analysis of 1-min intervals showed that PETF occurred in the first minute. A review of the literature suggests that a pause in tongue-flicking and delay of searching movements are absent in lizards and the few nonvenomous colubrid snakes tested. The delayed onset of SICS may be a specific adaptation of some viperid snakes to allow potentially dangerous prey to be rendered harmless by venom following voluntary release after envenomation and preceding further physical contact with the prey.  相似文献   
47.
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   
48.
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   
49.
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   
50.
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   
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