全文获取类型
收费全文 | 1803篇 |
免费 | 76篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 320篇 |
金属工艺 | 45篇 |
机械仪表 | 24篇 |
建筑科学 | 62篇 |
矿业工程 | 9篇 |
能源动力 | 46篇 |
轻工业 | 137篇 |
水利工程 | 15篇 |
石油天然气 | 7篇 |
无线电 | 164篇 |
一般工业技术 | 365篇 |
冶金工业 | 432篇 |
原子能技术 | 15篇 |
自动化技术 | 226篇 |
出版年
2023年 | 13篇 |
2022年 | 27篇 |
2021年 | 36篇 |
2020年 | 35篇 |
2019年 | 41篇 |
2018年 | 48篇 |
2017年 | 44篇 |
2016年 | 40篇 |
2015年 | 30篇 |
2014年 | 48篇 |
2013年 | 87篇 |
2012年 | 81篇 |
2011年 | 115篇 |
2010年 | 86篇 |
2009年 | 58篇 |
2008年 | 103篇 |
2007年 | 76篇 |
2006年 | 69篇 |
2005年 | 74篇 |
2004年 | 57篇 |
2003年 | 65篇 |
2002年 | 45篇 |
2001年 | 26篇 |
2000年 | 34篇 |
1999年 | 33篇 |
1998年 | 26篇 |
1997年 | 35篇 |
1996年 | 35篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 20篇 |
1991年 | 11篇 |
1990年 | 22篇 |
1989年 | 24篇 |
1988年 | 18篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 18篇 |
1984年 | 13篇 |
1983年 | 25篇 |
1982年 | 13篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1979年 | 26篇 |
1978年 | 16篇 |
1977年 | 18篇 |
1976年 | 10篇 |
1973年 | 8篇 |
1972年 | 8篇 |
排序方式: 共有1881条查询结果,搜索用时 15 毫秒
61.
Joel Lanir Alan J. Wecker Tsvi Kuflik Yasmin Felberbaum 《Personal and Ubiquitous Computing》2016,20(4):635-651
We conducted an exploratory study that examines the use of shared mobile displays such as mobile projectors and tablets to support group activities. We compare how a small group of visitors use either a shared display or personal individual devices in a museum visit context, in both a navigation task and a media viewing task. Group proximity, decision making, leadership patterns, and interaction between group members as well as attitudes are analyzed. We report on various usage patterns observed with group use of shared displays and discuss user preferences in comparison with the non-shared handheld alternative. Results show how mobile shared displays can support and enhance the group experience, by providing a shared mobile environment. Mobile shared displays increase group cohesiveness as was shown by increased proximity and amount of discussion by participants. Users perceive the use of shared displays as both useful and enjoyable, with the caveat that many users still want to retain individual control. We discuss this trade-off between groupness and individual control, as well as provide an analysis of the relative advantages of each shared display option. 相似文献
62.
63.
Dasagrandhi Chakradhar Ellamar Joel B. Kim Young Soon Kim Hak-Ryul 《Food science and biotechnology》2016,25(6):1671-1675
Food Science and Biotechnology - We analyzed the antimicrobial potential of a novel furan fatty acid, 7,10-epoxyoctadeca-7,9-dienoic acid (7,10-EODA) against methicillin-resistant and -sensitive S.... 相似文献
64.
Joel. L. Plawsky William N. Gill Ravi S. Achanta 《Journal of Materials Science: Materials in Electronics》2012,23(1):48-55
Copper solubility in low-k dielectrics has been shown to be a major factor in decreasing the useful lifetime of an interconnect.
A number of groups have shown experimentally that increased surface oxygen concentration, increased moisture content in the
dielectric, and an increase in interfacial copper concentration from chemical–mechanical polishing all contribute to accelerated
failure. Here, we assumed that all these processes led to an increase in the solubility of metal at the SiO2/metal. We systematically varied the value of the interfacial solubility, Ce over a wide range and showed that the solubility strongly affects the distribution of copper and the local electric field
within the dielectric. This changes the mechanism by which failure occurs from one where copper must penetrate all the way
through the dielectric to one where copper penetration is limited to a thin layer near the surface. The solubility levels
required to alter the failure mechanism, 1026–1027 atoms/m3, are within the realm of possibility and have been reported in the context of fabricating Cu-SiO2 resistive switching elements for memory applications. 相似文献
65.
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
66.
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
67.
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
68.
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
69.
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
70.
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