全文获取类型
收费全文 | 1972篇 |
免费 | 59篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 32篇 |
综合类 | 2篇 |
化学工业 | 776篇 |
金属工艺 | 65篇 |
机械仪表 | 52篇 |
建筑科学 | 57篇 |
矿业工程 | 12篇 |
能源动力 | 85篇 |
轻工业 | 103篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
武器工业 | 3篇 |
无线电 | 137篇 |
一般工业技术 | 255篇 |
冶金工业 | 81篇 |
原子能技术 | 9篇 |
自动化技术 | 363篇 |
出版年
2023年 | 9篇 |
2022年 | 77篇 |
2021年 | 112篇 |
2020年 | 23篇 |
2019年 | 36篇 |
2018年 | 53篇 |
2017年 | 49篇 |
2016年 | 73篇 |
2015年 | 48篇 |
2014年 | 64篇 |
2013年 | 137篇 |
2012年 | 100篇 |
2011年 | 98篇 |
2010年 | 110篇 |
2009年 | 79篇 |
2008年 | 96篇 |
2007年 | 71篇 |
2006年 | 54篇 |
2005年 | 61篇 |
2004年 | 54篇 |
2003年 | 51篇 |
2002年 | 48篇 |
2001年 | 37篇 |
2000年 | 23篇 |
1999年 | 27篇 |
1998年 | 25篇 |
1997年 | 29篇 |
1996年 | 32篇 |
1995年 | 20篇 |
1994年 | 26篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 10篇 |
1988年 | 21篇 |
1987年 | 18篇 |
1986年 | 14篇 |
1985年 | 15篇 |
1984年 | 26篇 |
1983年 | 26篇 |
1982年 | 18篇 |
1981年 | 23篇 |
1980年 | 15篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1973年 | 3篇 |
排序方式: 共有2037条查询结果,搜索用时 0 毫秒
51.
On-line Algorithm for Blind Signal Extraction of Arbitrarily Distributed,but Temporally Correlated Sources Using Second Order Statistics 总被引:4,自引:0,他引:4
Most of the algorithms for blind separation/extraction and independent component analysis (ICA) can not separate mixtures of sources with extremely low kurtosis or colored Gaussian sources. Moreover, to separate mixtures of super- and sub-Gaussian signals, it is necessary to use adaptive (time-variable) or switching nonlinearities which are controlled via computationally intensive measures, such as estimation of the sign of kurtosis of extracted signals. In this paper, we develop a very simple neural network model and an efficient on-line adaptive algorithm that sequentially extract temporally correlated sources with arbitrary distributions, including colored Gaussian sources and sources with extremely low values (or even zero) of kurtosis. The validity and performance of the algorithm have been confirmed by extensive computer simulation experiments. 相似文献
52.
Stefan Kiefer Andrzej S. Murawski Jo?l Ouaknine Bj?rn Wachter James Worrell 《Formal Aspects of Computing》2012,24(4-6):671-678
Herman’s algorithm is a synchronous randomized protocol for achieving self-stabilization in a token ring consisting of N processes. The interaction of tokens makes the dynamics of the protocol very difficult to analyze. In this paper we study the distribution of the time to stabilization, assuming that there are three tokens in the initial configuration. We show for arbitrary N and for an arbitrary timeout t that the probability of stabilization within time t is minimized by choosing as the initial three-token configuration the configuration in which the tokens are placed equidistantly on the ring. Our result strengthens a corollary of a theorem of McIver and Morgan (Inf. Process Lett. 94(2): 79–84, 2005), which states that the expected stabilization time is minimized by the equidistant configuration. 相似文献
53.
In this paper the conjugate fluid flow and energy transport problem (involving conduction-convection-radiation heat transfer) resulting from the Czochralski crystal growth process is analysed. The solidifying material is treated as a pure and semitransparent substance with material properties depending neither on temperature nor on the wavelength. The solution of the problem is obtained iteratively using two computer codes: FLUENT, a commercial CFD package, and BEM-based in-house code capable of analysing the radiative heat transfer in the entire computational domain.Obtained results not only show velocity field and temperature distribution within the bodies under consideration but also demonstrate the influence of thermal radiation on these quantities. 相似文献
54.
We present a new learning algorithm for the blind separation of independent source signals having non-zero skewness (the 3rd-order cumulant) (the source signals have non-symmetric probability distribution.), from their linear mixtures. It is shown that for a class of source signals whose probability distribution functions is not symmetric, a simple adaptive learning algorithm using quadratic function (f(x)=x2) is very efficient for blind source separation task. It is proved that all stable equilibria of the proposed learning algorithm are desirable solutions. Extensive computer simulation experiments confirmed the validity of the proposed algorithm. 相似文献
55.
Andrzej Dziech Przemysław Ślusarczyk Bernd Tibken 《Journal of Intelligent and Robotic Systems》2004,39(4):447-458
In this paper an image data compression scheme based on Periodic Haar Piecewise-Linear (PHL) transform and quantization tables is proposed. Effectiveness of the compression for different classes of images is evaluated. The comparison of the compression quality using PHL and DCT transforms is given. 相似文献
56.
Andrzej Neimitz 《Engineering Fracture Mechanics》2004,71(11):1585-1600
In the paper the classical Dugdale model has been generalized taking into account the influence of the specimen thickness, in-plane constraint as well as the effect of the strain hardening on the level of stress distribution within the strip yield zone (SYZ). Modification has been performed utilizing Huber, Mises, Hencky as well as Tresca yield hypotheses and Guo Wanlin Tz coefficient. Results are presented in a form useful for applications. As an example, the modified model has been applied to draw the failure assessment diagram (FAD). New FAD’s have been compared with others adopted from the SINTAP procedures. 相似文献
57.
In this paper, we investigate formulation of non-local memory effect hysteretic loops in presliding domain of friction by examining the dynamic responses of a single-degree-of-freedom friction oscillator. We modify the Maxwell slip model introducing characteristic features of asperities and perform detailed examination of the system from two perspectives. The first one, termed by us as microscale, presents contribution of each individual asperity to the total friction force, whereas the second one, termed by us as macroscale, concerns friction force behaviour of the whole model treated as the unity, with a special emphasis on non-local memory effect hysteretic loops formulation, complemented by time responses. 相似文献
58.
Eliza Judasz Natalia Lisiak Przemysaw Kopczyski Magdalena Taube Baej Rubi 《International journal of molecular sciences》2022,23(21)
Currently, breast cancer appears to be the most widespread cancer in the world and the most common cause of cancer deaths. This specific type of cancer affects women in both developed and developing countries. Prevention and early diagnosis are very important factors for good prognosis. A characteristic feature of cancer cells is the ability of unlimited cell division, which makes them immortal. Telomeres, which are shortened with each cell division in normal cells, are rebuilt in cancer cells by the enzyme telomerase, which is expressed in more than 85% of cancers (up to 100% of adenocarcinomas, including breast cancer). Telomerase may have different functions that are related to telomeres or unrelated. It has been shown that high activity of the enzyme in cancer cells is associated with poor cell sensitivity to therapies. Therefore, telomerase has become a potential target for cancer therapies. The low efficacy of therapies has resulted in the search for new combined and more effective therapeutic methods, including the involvement of telomerase inhibitors and telomerase-targeted immunotherapy. 相似文献
59.
60.
Daria Wojciechowska Micha Taube Karolina Ruciska Joanna Maksim Maciej Kozak 《International journal of molecular sciences》2022,23(21)
Human cystatin C (HCC), an amyloidogenic protein, forms dimers and higher oligomers (trimers, tetramers and donut like large oligomers) via a domain-swapping mechanism. The aim of this study was the characterization of the HCC oligomeric states observed within the pH range from 2.2 to 10.0 and also in conditions promoting oligomerization. The HCC oligomeric forms obtained in different conditions were characterized using size exclusion chromatography, dynamic light scattering and small-angle X-ray scattering. The marked ability of HCC to form tetramers at low pH (2.3 or 3.0) and dimers at pH 4.0–5.0 was observed. HCC remains monomeric at pH levels above 6.0. Based on the SAXS data, the structure of the HCC tetramer was proposed. Changes in the environment (from acid to neutral) induced a breakdown of the HCC tetramers to dimers. The tetrameric forms of human cystatin C are formed by the association of the dimers without a domain-swapping mechanism. These observations were confirmed by their dissociation to dimers at pH 7.4. 相似文献