全文获取类型
收费全文 | 1513篇 |
免费 | 78篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
综合类 | 2篇 |
化学工业 | 273篇 |
金属工艺 | 22篇 |
机械仪表 | 29篇 |
建筑科学 | 81篇 |
矿业工程 | 1篇 |
能源动力 | 49篇 |
轻工业 | 108篇 |
水利工程 | 15篇 |
石油天然气 | 2篇 |
无线电 | 85篇 |
一般工业技术 | 423篇 |
冶金工业 | 215篇 |
原子能技术 | 13篇 |
自动化技术 | 257篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 10篇 |
2021年 | 42篇 |
2020年 | 20篇 |
2019年 | 27篇 |
2018年 | 33篇 |
2017年 | 31篇 |
2016年 | 38篇 |
2015年 | 44篇 |
2014年 | 71篇 |
2013年 | 87篇 |
2012年 | 92篇 |
2011年 | 134篇 |
2010年 | 91篇 |
2009年 | 80篇 |
2008年 | 108篇 |
2007年 | 114篇 |
2006年 | 93篇 |
2005年 | 88篇 |
2004年 | 54篇 |
2003年 | 49篇 |
2002年 | 38篇 |
2001年 | 27篇 |
2000年 | 17篇 |
1999年 | 18篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1594条查询结果,搜索用时 546 毫秒
61.
Iliescu Florina Silvia Teo Jeremy Choon Meng Vrtacnik Danilo Taylor Hayden Iliescu Ciprian 《Microsystem Technologies》2018,24(7):2905-2912
Microsystem Technologies - Cell transplantation traditionally employs needles to inject donor cells into tissues to treat certain diseases. However, it is difficult for the current method to... 相似文献
62.
Mining blasts may be defined as the use of explosive charges in a controlled manner by following a tightly controlled timing sequence according to an assigned firing order. Changes of timing between charges may result in an altered firing order and failure of the blasting sequence, which can cause high vibration levels, poor fragmentation, and/or an undesirable rock mass movement direction. Despite the importance of timing in determining mine blast results, there exists a lack of methodologies or tools with which to assess performance of a complete blast based on delay type and timing sequence. This document applies reliability engineering principles to evaluate the performance of a mine blast. The analyses are based on test results of the accuracy and precision of electronic and pyrotechnic detonators for typical firing times used in a surface coal mine, but may be applied to a variety of mines and timing scenarios. 相似文献
63.
Sergio Gómez-Alonso Vanessa J. Collins David Vauzour Ana Rodríguez-Mateos Giulia Corona Jeremy P.E. Spencer 《Food chemistry》2012,130(3):493-500
The moderate consumption of red wine has been proposed to reduce the incidence of colorectal cancer. Its anti-cancer action my in part be mediated by the actions of polyphenols on colon cancer epithelial cells. We show that a red wine phenolic (50 μg/ml) extract devoid of anthocyanins (removed to reflect polyphenol bioavailability to the large intestine) and the major red wine flavonols quercetin, myricetin, laricitrin and syringetin (50 μM) are capable of inhibiting the proliferation of colorectal epithelial adenocarcinoma cells. This anti-proliferative activity was partly mediated by the direct cytotoxic actions of flavonols and also their ability to cause a significant cell cycle blockage in G2/M. The anti-proliferative effects induced by flavonols were preceded, in most cases, by a strong and significant reduction of cyclooxygenase-2 (COX-2) and cyclin D1 expression. These results indicate that the observed inverse correlation between colon cancer and a moderate red wine intake may be partly mediated by the actions of red wine flavonols on the growth of cancer cells. 相似文献
64.
65.
Scientometrics - The Small Business Innovation Research (SBIR) program is the primary source of public funding in the United States for research by small firms on new technologies, and the National... 相似文献
66.
The corrosion behavior and oxide structure of 9CrODS steel in supercritical water has been studied. Samples were exposed to supercritical water at 500 and 600 °C for times of 2, 4 and 6 weeks. The oxide structure was studied using microbeam synchrotron X-ray diffraction and fluorescence analysis. The 600 °C samples exhibited a three-layer structure with Fe3O4 in the outer layer, a mixture of FeCr2O4 and Fe3O4 in the inner layer, and a mixture of metal and oxide grains (FeCr2O4 and Cr2O3) in the diffusion layer. Between the 2 and 4-week samples exposed to 600 °C supercritical water, a Cr2O3 film appeared at the diffusion layer-metal interface which appears to be associated with slower oxidation of the metal. The 500 °C samples also showed a three-layer structure, but both the outer and inner oxide layers contained mainly Fe3O4, and the diffusion layer contained much fewer oxide precipitates and was a solid solution of oxygen ahead of the oxide front. 相似文献
67.
Jeremy Agte Olivier de Weck Jaroslaw Sobieszczanski-Sobieski Paul Arendsen Alan Morris Martin Spieck 《Structural and Multidisciplinary Optimization》2010,40(1-6):17-33
This paper is a summary of topics presented and discussed at the 2006 European–U.S. Multidisciplinary Optimization (MDO) Colloquium in Goettingen, Germany, attended by nearly seventy professionals from academia, industry, and government. An attempt is made to accurately reflect the issues discussed by this diverse group, qualified by interest, experience, and accomplishment to present an opinion about the state-of-the-art, trends, and developments in Multidisciplinary Design Optimization. As such, its main purpose is to provide suggestions and stimulus for future research in the field. The predominant content of the colloquium was centered on aerospace, with a few contributions from the automotive industry, and this is reflected in the article. Due to the timeframe that has passed since the conclusion of the workshop, the authors have updated topics where appropriate to reflect observed developments over the past 3 years. Finally, rather than dwelling extensively on past accomplishments and current capabilities in MDO we focus on the needs and identified shortcomings from the colloquium which lead to potential future research directions. A brief MDO background is provided to set the discussion in its proper context. 相似文献
68.
Xinghua Yu Jeremy L. Caron S. S. Babu John C. Lippold Dieter Isheim David N. Seidman 《Metallurgical and Materials Transactions A》2011,42(12):3669-3679
BlastAlloy 160 (BA160) is a low-carbon martensitic steel strengthened by copper and M2C precipitates. Heat-affected zone (HAZ) microstructure evaluation of BA160 exhibited softening in samples subjected to the
coarse-grained HAZ thermal simulations of this steel. This softening is partially attributed to dissolution of copper precipitates
and metal carbides. After subjecting these coarse-grained HAZs to a second weld thermal cycle below the A
c1 temperature (at which austenite begins to form on heating), recovery of strength was observed. Atom-probe tomography and
microhardness analyses correlated this strength recovery to re-precipitation of copper precipitates and metal carbides. A
continuum model is proposed to rationalize strengthening and softening in the HAZ regions of BlastAlloy 160. 相似文献
69.
Locking‐free discontinuous finite elements for the upper bound yield design of thick plates 下载免费PDF全文
Jeremy Bleyer Canh Van Le Patrick de Buhan 《International journal for numerical methods in engineering》2015,103(12):894-913
This work investigates the formulation of finite elements dedicated to the upper bound kinematic approach of yield design or limit analysis of Reissner–Mindlin thick plates in shear‐bending interaction. The main novelty of this paper is to take full advantage of the fundamental difference between limit analysis and elasticity problems as regards the class of admissible virtual velocity fields. In particular, it has been demonstrated for 2D plane stress, plane strain or 3D limit analysis problems that the use of discontinuous velocity fields presents a lot of advantages when seeking for accurate upper bound estimates. For this reason, discontinuous interpolations of the transverse velocity and the rotation fields for Reissner–Mindlin plates are proposed. The subsequent discrete minimization problem is formulated as a second‐order cone programming problem and is solved using the industrial software package MOSEK . A comprehensive study of the shear‐locking phenomenon is also conducted, and it is shown that discontinuous elements avoid such a phenomenon quite naturally whereas continuous elements cannot without any specific treatment. This particular aspect is confirmed through numerical examples on classical benchmark problems and the so‐obtained upper bound estimates are confronted to recently developed lower bound equilibrium finite elements for thick plates. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
70.