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951.
Sbrocco Tracy; Nedegaard Randall C.; Stone Jay M.; Lewis Evelyn L. 《Canadian Metallurgical Quarterly》1999,67(2):260
Twenty-four obese women were randomly assigned to 1 of 2 group treatments: behavioral choice treatment (BCT) or traditional behavioral treatment (TBT). BCT uses decision theory to promote moderate behavior change that can be comfortably, and therefore permanently, maintained. Groups completed a moderate-intensity walking program and obtained feedback from computerized eating dairies. The TBT group evidenced greater weight loss at posttreatment. However, the TBT group also evidenced a trend to regain weight, whereas the BCT group continued a slow weight loss during follow-up. Exercise followed a similar pattern. Both groups decreased in restraint and increased in self-esteem. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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954.
白噪声发生器生成不同频率下输出功率密度恒定的频谱图。
这类发生器适用于低频响应较大或是有直流响应的测试电路。但是,由于存在粉红噪声(或称闪烁噪声),使频率范围延伸到几赫兹甚至更低的白噪声发生器变得十分复杂。半导体元件产生的噪声总是带有特征性的粉红噪声,即其输出功率密度幅值随频率降低而升高,转折频率为几十赫兹到几千赫兹。高阻值的电阻会产生带有自身闪烁噪声分量的噪声,噪声分量的值和特性随电阻制造技术的不同而发生变化。 相似文献
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956.
Engle Randall W.; Tuholski Stephen W.; Laughlin James E.; Conway Andrew R. A. 《Canadian Metallurgical Quarterly》1999,128(3):309
A study was conducted in which 133 participants performed 11 memory tasks (some thought to reflect working memory and some thought to reflect short-term memory), 2 tests of general fluid intelligence, and the Verbal and Quantitative Scholastic Aptitude Tests. Structural equation modeling suggested that short-term and working memories reflect separate but highly related constructs and that many of the tasks used in the literature as working memory tasks reflect a common construct. Working memory shows a strong connection to fluid intelligence, but short-term memory does not. A theory of working memory capacity and general fluid intelligence is proposed: The authors argue that working memory capacity and fluid intelligence reflect the ability to keep a representation active, particularly in the face of interference and distraction. The authors also discuss the relationship of this capability to controlled attention, and the functions of the prefrontal cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
957.
Sridhar B. Broto Chatterji G. Randall Grabbe S. 《Intelligent Transportation Systems, IEEE Transactions on》2000,1(4):190-198
Initiatives in air traffic management both in the United States and in Europe are aimed at providing air traffic controllers with automation tools to separate traffic, meet time constraints required for traffic flow and accommodate route preferences of users such as airlines. These efforts are expected to result in removal of restrictions on users preferred routes without compromising safety. Thus, aircraft will be able to fly optimal routes such as great circle and wind-optimal routes. NASA has developed the design for a new automation tool, referred to as the direct-to tool, which advises the controller on direct time-saving routes for any aircraft irrespective of levels of equipage. In contrast to earlier studies on the potential benefits of direct routes in the National Airspace System, the objective of the paper is to evaluate the benefits based on a controller tool. The paper describes the benefits of applying this algorithm to the 20 air route traffic control centers within the United States. Benefits are measured in terms of the total time savings accrued by flying the direct route. Results are described for three different implementations dependent on the search region bounding each air route traffic control center. The first region exactly encloses the air route traffic control center airspace, the second is the smallest rectangular bounding region while the third is a bigger rectangular bounding region approximately twice as large as the second region. It is shown that the application of the direct-to routing algorithm does not significantly alter the number of conflicts and their spatial distribution compared to the case in which the aircraft fly along the airways. The results presented in the paper suggest that the direct-to routing algorithm can provide significant cost savings to the users without adversely impacting the air traffic management functions 相似文献
958.
Carlos E. Thomaz Fabio L. S. Duran Geraldo F. Busatto Duncan F. Gillies Daniel Rueckert 《Journal of Mathematical Imaging and Vision》2007,29(2-3):95-106
Multivariate statistical discrimination methods are suitable not only for classification but also for characterization of differences between a reference group of patterns and the population under investigation. In the last years, statistical methods have been proposed to classify and analyse morphological and anatomical structures of medical images. Most of these techniques work in high-dimensional spaces of particular features such as shapes or statistical parametric maps and have overcome the difficulty of dealing with the inherent high dimensionality of medical images by analysing segmented structures individually or performing hypothesis tests on each feature separately. In this paper, we present a general multivariate linear framework that addresses the small sample size problem in medical images. The goal is to identify and analyse the most discriminating hyper-plane separating two populations using all the intensity features simultaneously rather than segmented versions of the data separately or feature-by-feature. To demonstrate the performance of the multivariate linear framework we carry out experimental results on artificially generated data set and on a real medical data composed of magnetic resonance images (MRI) of subjects suffering from Alzheimer’s disease (AD) compared to an elderly healthy control group. To our knowledge this is the first multivariate statistical analysis of the human brain in AD that uses the whole features (texture + shapes) simultaneously rather than segmented version of the images. The conceptual and mathematical simplicity of the approach involves the same operations irrespective of the complexity of the experiment or nature of the spatially normalized data, giving multivariate results that are plausible and easy to interpret by the clinicians. 相似文献
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960.
Howard M.A. III Abkes B.A. Ollendieck M.C. Noh M.D. Ritter C. Gillies G.T. 《IEEE transactions on bio-medical engineering》1999,46(7):891-894
The advent of high-precision magnetic and robotic computer-controlled neurosurgery systems makes it necessary to determine the range of forces that will be encountered by the probes of such devices as they are guided through the brain tissues to intraparenchymal targets. We have measured the penetration forces on 2.5-mm spheres and the drag forces on 3.0-mm ventricular shunt catheters advanced 2.0-3.5 cm deep into in vivo human brain tissues (in patients about to have those tissues resected during epilepsy surgery) at rates of approximately 0.33 mm s-1. Penetration forces of (8 +/- 2) grams were found for the spherical probe once it passed 0.5 cm below the cortical surface, and frictional drags of (2.8 +/- 0.3) grams cm-1 were exerted on the catheters. The variable nature of these forces is discussed and the results are compared with earlier studies on experimental animal tissues and brain phantom gelatins. The implications of these results for magnetic and robotic surgery systems are considered. 相似文献