全文获取类型
收费全文 | 134112篇 |
免费 | 3817篇 |
国内免费 | 571篇 |
专业分类
电工技术 | 1518篇 |
综合类 | 2377篇 |
化学工业 | 22036篇 |
金属工艺 | 6647篇 |
机械仪表 | 6002篇 |
建筑科学 | 3289篇 |
矿业工程 | 587篇 |
能源动力 | 3353篇 |
轻工业 | 7632篇 |
水利工程 | 1531篇 |
石油天然气 | 435篇 |
武器工业 | 3篇 |
无线电 | 17479篇 |
一般工业技术 | 27443篇 |
冶金工业 | 6768篇 |
原子能技术 | 951篇 |
自动化技术 | 30449篇 |
出版年
2024年 | 56篇 |
2023年 | 614篇 |
2022年 | 947篇 |
2021年 | 1605篇 |
2020年 | 1178篇 |
2019年 | 1276篇 |
2018年 | 15536篇 |
2017年 | 14475篇 |
2016年 | 11465篇 |
2015年 | 1999篇 |
2014年 | 2477篇 |
2013年 | 3463篇 |
2012年 | 6488篇 |
2011年 | 13139篇 |
2010年 | 10900篇 |
2009年 | 8460篇 |
2008年 | 9505篇 |
2007年 | 9856篇 |
2006年 | 2300篇 |
2005年 | 3039篇 |
2004年 | 2780篇 |
2003年 | 2746篇 |
2002年 | 1944篇 |
2001年 | 1314篇 |
2000年 | 1258篇 |
1999年 | 1073篇 |
1998年 | 1781篇 |
1997年 | 1134篇 |
1996年 | 955篇 |
1995年 | 636篇 |
1994年 | 522篇 |
1993年 | 470篇 |
1992年 | 330篇 |
1991年 | 317篇 |
1990年 | 279篇 |
1989年 | 261篇 |
1988年 | 233篇 |
1987年 | 190篇 |
1986年 | 127篇 |
1985年 | 132篇 |
1984年 | 105篇 |
1983年 | 76篇 |
1981年 | 44篇 |
1977年 | 47篇 |
1976年 | 71篇 |
1968年 | 48篇 |
1966年 | 45篇 |
1965年 | 46篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
Harshavardhan Mohan Jeong-Muk Lim Se-Won Lee Min Cho Yool-Jin Park Kamala-Kannan Seralathan Byung-Taek Oh 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2020,95(1):297-307
The cover image is based on the Research Article V2O5/RGO/Pt nanocomposite on oxytetracycline degradation and pharmaceutical effluent detoxification by Mohan, H et al., DOI: 10.1002/jctb.6238 .
15.
Mobile software applications have to cope with a particular environment that involves small size, limited resources, high autonomy requirements, competitive business models and many other challenges. To provide development guidelines that respond to these needs, several practices have been introduced; however, it is not clear how these guidelines may contribute to solve the issues present in the mobile domain. Furthermore, the rapid evolution of the mobile ecosystem challenges many of the premises upon which the proposed practices were designed. In this paper, we present a survey of the literature on software assurance practices for mobile applications, with the objective of describing them and assessing their contribution and success. We identified, organized and reviewed a body of research that spans in three levels: software development processes, software product assurance practices, and software implementation practices. By carrying out this literature survey, we reviewed the different approaches that researchers on Software Engineering have provided to address the needs that raise in the mobile software development arena. Moreover, we review the evolution of these practices, identifying how the constant changes and modernization of the mobile execution environment has impacted the methods proposed in the literature. Finally, we introduced discussion on the application of these practices in a real productive setting, opening an area for further research that may determine if practitioners have followed the proposed assurance paradigms. 相似文献
16.
A. A. Babenko V. I. Zhuchkov L. A. Smirnov A. V. Sychev A. A. Akberdin A. S. Kim M. F. Vitushchenko A. A. Dobromilov 《Steel in Translation》2015,45(11):883-886
A technology for slag formation in the ladle–furnace unit is considered; the slag is based on the CaO–SiO2–MgO–Al2O3–B2O3 system. This technology permits both microalloying of the steel with boron (reduced from the oxide phase) and desulfurization of the steel. The resulting boron content in the steel is 0.001–0.008%; the sulfur content in low-alloy steel and pipe steel is low (0.004–0.010%); and the consumption of manganese ferroalloys is reduced to 0.5 kg/t for 08кп steel and 1.4 kg/t for 09Г2C steel. In addition, the proposed technology increases the strength of the rolled steel, without loss in its plasticity; and reduces the environmental impact thanks to the replacement of fluorspar by colemanite. 相似文献
17.
This paper presents an integrated passive damping approach in hybrid metal-CFRP parts for structural applications. In this concept a viscoelastic material is embedded in the joint zone of the hybrid component. To examine the connection strength single-lap-joint specimens were produced and tested and the influence of the used material combinations, different surface structures, and different process parameters i.e. the moment of cross-linking were evaluated. Afterwards, the metal-CFRP hybrids were tested in quasi-static tests to assess their connection strength and failure behaviour. Dynamic cyclic tensile tests with step-wise increased loading conditions were performed to determine the specimens damping behaviour and to estimate their fatigue performance. Finally, these results are compared to a state of the art metal-CFRP hybrid with rivets connecting both materials. 相似文献
18.
In this paper, we consider the classical finite mixture model, which is an effective tool for modeling lifetime distributions for random samples from heterogeneous populations. We discuss new results on stochastic comparison for two finite mixtures when each of them is drawn from one of the following semiparametric families, i.e., proportional hazards, accelerated lifetime and proportional reversed hazards. 相似文献
19.
20.