全文获取类型
收费全文 | 2646篇 |
免费 | 85篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 57篇 |
综合类 | 1篇 |
化学工业 | 356篇 |
金属工艺 | 52篇 |
机械仪表 | 34篇 |
建筑科学 | 71篇 |
矿业工程 | 9篇 |
能源动力 | 51篇 |
轻工业 | 160篇 |
水利工程 | 16篇 |
石油天然气 | 7篇 |
无线电 | 232篇 |
一般工业技术 | 417篇 |
冶金工业 | 839篇 |
原子能技术 | 25篇 |
自动化技术 | 406篇 |
出版年
2023年 | 14篇 |
2022年 | 31篇 |
2021年 | 38篇 |
2020年 | 38篇 |
2019年 | 43篇 |
2018年 | 51篇 |
2017年 | 52篇 |
2016年 | 46篇 |
2015年 | 34篇 |
2014年 | 52篇 |
2013年 | 118篇 |
2012年 | 90篇 |
2011年 | 132篇 |
2010年 | 99篇 |
2009年 | 71篇 |
2008年 | 116篇 |
2007年 | 91篇 |
2006年 | 86篇 |
2005年 | 88篇 |
2004年 | 69篇 |
2003年 | 75篇 |
2002年 | 58篇 |
2001年 | 33篇 |
2000年 | 52篇 |
1999年 | 55篇 |
1998年 | 109篇 |
1997年 | 94篇 |
1996年 | 86篇 |
1995年 | 63篇 |
1994年 | 57篇 |
1993年 | 51篇 |
1992年 | 33篇 |
1991年 | 29篇 |
1990年 | 35篇 |
1989年 | 43篇 |
1988年 | 38篇 |
1987年 | 46篇 |
1986年 | 26篇 |
1985年 | 36篇 |
1984年 | 23篇 |
1983年 | 35篇 |
1982年 | 22篇 |
1981年 | 25篇 |
1980年 | 21篇 |
1979年 | 34篇 |
1978年 | 27篇 |
1977年 | 29篇 |
1976年 | 32篇 |
1973年 | 17篇 |
1972年 | 13篇 |
排序方式: 共有2733条查询结果,搜索用时 31 毫秒
101.
Design,refinement, implementation and prototype testing of a reconfigurable lathe-mill 总被引:1,自引:0,他引:1
This article documents the design, refinement, and implementation of a reconfigurable machine tool that provides a flexible platform for turning and milling. Advances in the design and capabilities of machine tools drive modern industry. In fact, the expanding capabilities of the machines permit novel and economic changes in the manufacturing and design of products. After the flexible manufacturing (FMS) boom, a more recent, but no less significant, area of machine development involves the reconfiguration of milling machines. This reconfigurability can also be applied to lathe-mills. The present work demonstrates satisfactorily the reconfiguration characteristics of modularity, integrability, and convertibility. We prototype and test a completely functional bench top reconfigurable lathe mill machine implemented using a $10,000 USD budget and developed following a synthesized machine tool product development methodology that begins with concept design and cutting forces to end in prototyping. In addition to reasonable results in runout, positioning, and surface roughness, the machine demonstrates the capability to produce parts with a Cpk of 1.009, thereby demonstrating the ability to fabricate this type of machine in Mexico for the local jewelry industry. 相似文献
102.
Joel E. Cohen 《技术计量学》2013,55(2):206-207
The experimental error variance in a response surface model with a block effect has traditionally been assumed to be constant. In some experimental situations, however, this variance may be different for the different blocks that compose the associated design. This article discusses the analysis of a response surface model with a random block effect and heterogeneous error variances among the blocks. The model includes interactions between the fixed polynomial effects and the block effect. Procedures for estimating and testing the fixed effects and the random effects in the model are described. In particular, ANOVA-based procedures for testing equality of the error variances and testing the random effects are introduced. 相似文献
103.
Joel K. Jolayemi 《国际生产研究杂志》2013,51(11):2591-2608
Models were developed for the design of np-charts with three and four control regions, respectively. Procedures for obtaining solutions to the models were also developed. Numerical examples are given to illustrate the model and to study the properties of the charts. The results of the numerical examples show that changes in the specified values of most of the risks and powers associated with the chart--particularly those classified as 'critical risks'--affect the values of the design parameters of the charts. The OC and power curves drawn for some of the numerical examples show that the discriminatory power of an np-chart with multiple control regions depends on the values of the design parameters and the number of control regions--the more the number of its control regions, the less the discriminatory power of the chart, and vice versa. 相似文献
104.
Xin Zhong Luojing Xiang Sebastien Royer Sabine Valange Joel Barrault Hui Zhang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(7):970-977
BACKGROUND: A mesoporous alumina supported nanosized Fe2O3 was prepared through an original synthesis procedure and used as a heterogeneous catalyst for the Fenton process degradation of the model azo dye C.I. Acid Orange 7 enhanced by ultrasound irradiation (US/Fe2O3‐Al2O3‐meso/H2O2 system). The effect of various operating conditions was investigated, namely hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading. RESULTS: The results indicated that the degradation of C.I. Acid Orange 7 followed a pseudo‐first‐order kinetic model. There exists an optimal hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading for decolorization. The aggregate size of the spent catalyst was reduced after dispersion in water by ultrasonic irradiation. A very low level of iron leaching was observed ranging from < 0.1 to 0.23 mg L?1. The intermediate products of C.I. Acid Orange 7 degradation were identified using gas chromatography–mass spectrometry (GC‐MS). CONCLUSION: The optimal conditions for efficient C.I. Acid Orange 7 degradation were pH close to 3, hydrogen peroxide concentration 4 mmol L?1, catalyst loading 0.3 g L?1, and ultrasonic power 80 W. Copyright © 2011 Society of Chemical Industry 相似文献
105.
Zvolensky Michael J.; Marshall Erin C.; Johnson Kirsten; Hogan Julianna; Bernstein Amit; Bonn-Miller Marcel O. 《Canadian Metallurgical Quarterly》2009,17(1):31
The present investigation examines anxiety sensitivity, distress tolerance, and fear reactivity to bodily sensations in relation to Coping and Conformity marijuana use motives among a sample of young adult marijuana users (n = 135; 46.7% women; Mage = 20.45, SD = 5.0). After controlling for current marijuana use frequency (past 30 days), daily cigarette smoking rate, average volume of alcohol used over the past year, negative affectivity, and other marijuana use motives, anxiety sensitivity was significantly and uniquely associated with Coping and Conformity motives for marijuana use. Distress tolerance evidenced significant and unique incremental relations to Coping motives, whereas fear reactivity to bodily sensations was unrelated to any marijuana use motive. These results provide novel information related to the role of emotional sensitivity and tolerance factors as they pertain to specific types of motives for marijuana use among young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
Joseph Berry Tonio Buonassisi David A. Egger Gary Hodes Leeor Kronik Yueh‐Lin Loo Igor Lubomirsky Seth R. Marder Yitzhak Mastai Joel S. Miller David B. Mitzi Yaron Paz Andrew M. Rappe Ilan Riess Boris Rybtchinski Oscar Stafsudd Vladan Stevanovic Michael F. Toney David Zitoun Antoine Kahn David Ginley David Cahen 《Advanced materials (Deerfield Beach, Fla.)》2015,27(35):5102-5112
107.
Terry L. Friesz Jack Weiss Joel Gottfried 《Civil Engineering and Environmental Systems》2013,30(2):63-68
This paper reviews the concept of a diagonalization algorithm for use in solving traffic network equilibrium problems for which the arc cost and/or the origin-destination travel demand functions are asymmetric. Such functions are known to occur in realistic settings involving multiple modes or users. The computational performance of this algorithm for different degrees of travel demand asymmetry is then explored by a detailed numerical experiment since no previous results of this type have been reported. It is found that, through the use of progressive stopping tolerances, the impact of high degrees of travel demand function asymmetry on the computational burden associated with finding a traffic network equilibrium may be mitigated; in effect equilibrium problems with high degrees of demand asymmetry are little more difficult to solve than perfectly symmetric problems. 相似文献
108.
Identification and Structure–Activity Relationship Studies of Small‐Molecule Inhibitors of the Methyllysine Reader Protein Spindlin1
下载免费PDF全文
![点击此处可从《ChemMedChem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Dina Robaa Dr. Tobias Wagner Chiara Luise Dr. Luca Carlino Joel McMillan Dr. Ralf Flaig Prof. Dr. Roland Schüle Prof. Dr. Manfred Jung Prof. Dr. Wolfgang Sippl 《ChemMedChem》2016,11(20):2327-2338
The methyllysine reader protein Spindlin1 has been implicated in the tumorigenesis of several types of cancer and may be an attractive novel therapeutic target. Small‐molecule inhibitors of Spindlin1 should be valuable as chemical probes as well as potential new therapeutics. We applied an iterative virtual screening campaign, encompassing structure‐ and ligand‐based approaches, to identify potential Spindlin1 inhibitors from databases of commercially available compounds. Our in silico studies coupled with in vitro testing were successful in identifying novel Spindlin1 inhibitors. Several 4‐aminoquinazoline and quinazolinethione derivatives were among the active hit compounds, which indicated that these scaffolds represent promising lead structures for the development of Spindlin1 inhibitors. Subsequent lead optimization studies were hence carried out, and numerous derivatives of both lead scaffolds were synthesized. This resulted in the discovery of novel inhibitors of Spindlin1 and helped explore the structure–activity relationships of these inhibitor series. 相似文献
109.
110.
Ramn E. Narciandi Julio R. Fernandez Jos García Joel Madrazo Gabriel Padrn Lidia I. Novoa Luis Herrera 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1996,66(1):1-6
A fragment of the gp-36 gene of the Human Immunodeficiency Virus type 2 (HIV-2) was fused to a stabilizer sequence, which encodes for the first N-terminal 58 amino acids of the human interleukin-2. The fused protein was expressed under the control of the tryptophan promoter in Escherichia coli, and expressed as 20% of the total cellular protein. Transmission electron microscopy indicated that the fusion protein formed cytoplasmic insoluble inclusion bodies. Inclusion bodies were semipurified by a wash pellet cell procedure, rendering a material with a purity higher than 70% by SDS–polyacrylamide gel electrophoresis. After solubilization with urea, this preparation was further purified by gel-filtration chromatography up to 95% purity. 相似文献