全文获取类型
收费全文 | 2153篇 |
免费 | 69篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 34篇 |
综合类 | 3篇 |
化学工业 | 801篇 |
金属工艺 | 83篇 |
机械仪表 | 54篇 |
建筑科学 | 73篇 |
矿业工程 | 12篇 |
能源动力 | 94篇 |
轻工业 | 127篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
武器工业 | 3篇 |
无线电 | 143篇 |
一般工业技术 | 303篇 |
冶金工业 | 119篇 |
原子能技术 | 7篇 |
自动化技术 | 365篇 |
出版年
2023年 | 10篇 |
2022年 | 78篇 |
2021年 | 111篇 |
2020年 | 29篇 |
2019年 | 35篇 |
2018年 | 50篇 |
2017年 | 49篇 |
2016年 | 79篇 |
2015年 | 49篇 |
2014年 | 68篇 |
2013年 | 147篇 |
2012年 | 114篇 |
2011年 | 100篇 |
2010年 | 121篇 |
2009年 | 87篇 |
2008年 | 107篇 |
2007年 | 87篇 |
2006年 | 64篇 |
2005年 | 67篇 |
2004年 | 62篇 |
2003年 | 60篇 |
2002年 | 52篇 |
2001年 | 38篇 |
2000年 | 23篇 |
1999年 | 35篇 |
1998年 | 33篇 |
1997年 | 34篇 |
1996年 | 33篇 |
1995年 | 22篇 |
1994年 | 30篇 |
1993年 | 25篇 |
1992年 | 16篇 |
1991年 | 24篇 |
1990年 | 23篇 |
1989年 | 18篇 |
1988年 | 22篇 |
1987年 | 25篇 |
1986年 | 17篇 |
1985年 | 19篇 |
1984年 | 26篇 |
1983年 | 28篇 |
1982年 | 19篇 |
1981年 | 24篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1974年 | 3篇 |
排序方式: 共有2229条查询结果,搜索用时 15 毫秒
101.
Stefan Kiefer Andrzej S. Murawski Joël Ouaknine Björn Wachter James Worrell 《Formal Methods in System Design》2013,43(2):285-312
We present a detailed account of a translation from probabilistic call-by-value programs with procedures to Rabin’s probabilistic automata. The translation is fully abstract in that programs exhibit the same computational behaviour if and only if the corresponding automata are language-equivalent. Since probabilistic language equivalence is decidable, we can apply the translation to analyse the behaviour of probabilistic programs and protocols. We illustrate our approach on a number of case studies. 相似文献
102.
Aleksandra Maria Staszak Tomasz Andrzej Paw?owski 《International journal of molecular sciences》2014,15(6):10868-10891
The proteome of zygotic embryos of Acer platanoides L. was analyzed via high-resolution 2D-SDS-PAGE and MS/MS in order to: (1) identify significant physiological processes associated with embryo development; and (2) identify changes in the proteome of the embryo associated with the acquisition of seed dormancy. Seventeen spots were identified as associated with morphogenesis at 10 to 13 weeks after flowering (WAF). Thirty-three spots were associated with maturation of the embryo at 14 to 22 WAF. The greatest changes in protein abundance occurred at 22 WAF, when seeds become fully mature. Overall, the stage of morphogenesis was characterized by changes in the abundance of proteins (tubulins and actin) associated with the growth and development of the embryo. Enzymes related to energy supply were especially elevated, most likely due to the energy demand associated with rapid growth and cell division. The stage of maturation is crucial to the establishment of seed dormancy and is associated with a higher abundance of proteins involved in genetic information processing, energy and carbon metabolism and cellular and antioxidant processes. Results indicated that a glycine-rich RNA-binding protein and proteasome proteins may be directly involved in dormancy acquisition control, and future studies are warranted to verify this association. 相似文献
103.
104.
Studies on electromigration phenomenon in thick-film structures on alumina and LTCC substrates are presented in this paper. The effects of storage of Au and Ag electrode patterns in temperature range up to 300 °C under voltage bias were examined. The leakage characteristics of electrodes with 100 μm spacing at 50 V dc bias as a function of time and temperature are presented and analyzed. Scanning electron microscope (SEM) equipped with the energy-dispersive X-ray spectroscopy (EDX) detector was applied for determination of metal ions transport. Test structures with Au-based conductive material are much more resistant to electromigration than Ag-based layers. 相似文献
105.
Andrzej Kuliczkowski Urszula Kubicka Anna Parka 《Tunnelling and Underground Space Technology incorporating Trenchless Technology Research》2010,25(6):795-801
The paper presents not only the comparative analysis of the three standards (German, Danish and American) commonly used in Poland for the design of resin liners, but also the chosen problems involved with the design. The attached examples of calculations give a chance to investigate the influence of noticed differences in basic assumptions on the final results including the minimum, acceptable wall thickness of the linings used for trenchless renovation of gravitational sewers. 相似文献
106.
Extended HALS algorithm for nonnegative Tucker decomposition and its applications for multiway analysis and classification 总被引:1,自引:0,他引:1
Analysis of high dimensional data in modern applications, such as neuroscience, text mining, spectral analysis, chemometrices naturally requires tensor decomposition methods. The Tucker decompositions allow us to extract hidden factors (component matrices) with different dimension in each mode, and investigate interactions among various modalities. The alternating least squares (ALS) algorithms have been confirmed effective and efficient in most of tensor decompositions, especially Tucker with orthogonality constraints. However, for nonnegative Tucker decomposition (NTD), standard ALS algorithms suffer from unstable convergence properties, demand high computational cost for large scale problems due to matrix inverse, and often return suboptimal solutions. Moreover they are quite sensitive with respect to noise, and can be relatively slow in the special case when data are nearly collinear. In this paper, we propose a new algorithm for nonnegative Tucker decomposition based on constrained minimization of a set of local cost functions and hierarchical alternating least squares (HALS). The developed NTD-HALS algorithm sequentially updates components, hence avoids matrix inverse, and is suitable for large-scale problems. The proposed algorithm is also regularized with additional constraint terms such as sparseness, orthogonality, smoothness, and especially discriminant. Extensive experiments confirm the validity and higher performance of the developed algorithm in comparison with other existing algorithms. 相似文献
107.
Lukasz Pietrzak Przemyslaw Sowinski Joanna Bojda Ewa Piorkowska Andrzej Galeski 《应用聚合物科学杂志》2016,133(28)
We hypothesized that polymer crystal anisotropy is advantageous for toughening of polymer composites involving easy slip network of oriented crystalline layers around filler particles. To this end, composites of syndiotactic polypropylene (sPP) with high concentration of submicrometer calcium carbonate particles were prepared and examined because usual sPP crystals exhibit high packing anisotropy. The specific orientation of sPP lamellae around chalk grains was found, which is supposed to facilitate the plastic deformation of polymer matrices. The compression molded bars of the composite exhibited markedly higher Izod impact strength than those of neat sPP. Toughening was even enhanced in the injection molded composite, for which 4.5‐fold increase in the impact strength was achieved. Injection‐induced orientation of the disordered form I sPP crystals was enhanced in the composite. The injection molded tensile specimens exhibited also a good drawability. Debonding at chalk–sPP interface occurred both during the impact and tensile tests facilitating the plastic deformation of sPP matrix. Chalk did not have any significant influence on the thermal properties of the composites but it affected the rheological behavior, increasing the loss and storage moduli, and the viscosity. Highly filled sPP composite exhibited solid‐like behavior in a molten state with the storage modulus exceeding the loss modulus in the entire frequency range. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43651. 相似文献
108.
Jorge?OyarzúnEmail author Hugo?Maturana Andrzej?Paulo Anna?Pasieczna 《Mine Water and the Environment》2003,22(3):155-161
Abstract.
Active sediments from the Elqui River in Chile were
sampled 4 times at 10 sites during 2000. Concentrations of Ag,
Ba, Cd, Co, Cr, Hg, Mn, Mo, Ni, Pb, Sr, Ti, V, Al, Ca, Fe, K,
Mg, Na, P, and S were normal. Zinc levels were clearly high, and
those of Cu (hundred to thousands ppm) and As (tens to hundreds
ppm) were highly anomalous. Dissolved Cu (0.1-12.7 ppm) and Zn
(0.2-2.2 ppm) levels were also very high. The anomalies of the
upper tributaries are due to the El Indio–Tambo Au-Cu-As
district and large hydrothermal alteration zones at altitudes
between 3500–4500 m. Lower on the river, old and active tailing
waste deposits and on-going mining operations in the Talcuna Cu
(Pb) district are responsible. Partially eroded tailing deposits
in the alluvial plain of the Elqui River and its tributaries,
and especially in the El Indio-Tambo district, after mine
closure in 2000, warrant special attention. 相似文献
109.
110.
Katarzyna Grzybowska Zaneta Wojnarowska Andrzej Grzybowski Marian Paluch Juan M. Giussi M. Susana Cortizo Iwona Blaszczyk-Lezak Carmen Mijangos 《Polymer》2014
In this paper, dielectric and calorimetric studies of the small-molecule glass former allyl acetoacetate monomers as well as its newly synthetized homopolymer and copolymers with different styrene composition were performed in both the liquid and glassy states. The molecular dynamics studies by the broadband dielectric spectroscopy and the stochastic temperature modulated differential scanning calorimetry enabled us to explore relaxation processes of examined materials in the wide frequency range. We found that the copolymers reveal two co-existing glass transitions characterized by the glass transition temperatures, which are very close to those of the corresponding homopolymers. These results suggest that the copolymers exhibited some sequences of acetoacetate units with a microphase-separated morphology in agreement with the value of reactivity ratio previously determined. We investigated effects of copolymerization compositions on the glass transition temperature, the isobaric fragility index, the dielectric and calorimetric intensity, and the dynamic heterogeneity on the glass transitions of the materials. 相似文献