全文获取类型
收费全文 | 12765篇 |
免费 | 444篇 |
国内免费 | 58篇 |
专业分类
电工技术 | 260篇 |
综合类 | 16篇 |
化学工业 | 2278篇 |
金属工艺 | 367篇 |
机械仪表 | 361篇 |
建筑科学 | 220篇 |
矿业工程 | 73篇 |
能源动力 | 703篇 |
轻工业 | 1172篇 |
水利工程 | 190篇 |
石油天然气 | 82篇 |
无线电 | 1622篇 |
一般工业技术 | 2773篇 |
冶金工业 | 1545篇 |
原子能技术 | 198篇 |
自动化技术 | 1407篇 |
出版年
2024年 | 40篇 |
2023年 | 177篇 |
2022年 | 506篇 |
2021年 | 504篇 |
2020年 | 409篇 |
2019年 | 410篇 |
2018年 | 553篇 |
2017年 | 512篇 |
2016年 | 483篇 |
2015年 | 280篇 |
2014年 | 446篇 |
2013年 | 886篇 |
2012年 | 518篇 |
2011年 | 676篇 |
2010年 | 540篇 |
2009年 | 531篇 |
2008年 | 477篇 |
2007年 | 389篇 |
2006年 | 331篇 |
2005年 | 264篇 |
2004年 | 244篇 |
2003年 | 219篇 |
2002年 | 180篇 |
2001年 | 143篇 |
2000年 | 147篇 |
1999年 | 156篇 |
1998年 | 355篇 |
1997年 | 231篇 |
1996年 | 251篇 |
1995年 | 219篇 |
1994年 | 183篇 |
1993年 | 172篇 |
1992年 | 143篇 |
1991年 | 151篇 |
1990年 | 114篇 |
1989年 | 108篇 |
1988年 | 130篇 |
1987年 | 109篇 |
1986年 | 89篇 |
1985年 | 115篇 |
1984年 | 94篇 |
1983年 | 107篇 |
1982年 | 99篇 |
1981年 | 88篇 |
1980年 | 78篇 |
1979年 | 54篇 |
1978年 | 46篇 |
1977年 | 56篇 |
1976年 | 76篇 |
1975年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The electrochemical and corrosion behaviour of a nickel base super alloy (C-263) has been investigated in the deaerated binary and ternary solution mixture of concentrated phosphoric acid, acetic acid, sulphuric acid, nitric acid or water using potentiostatic technique at 35°C. The possibilities of electropolishing of this alloy in these solution mixtures have been also explored. The alloy showed distinct active, passive and transpassive behaviour in the experimental solutions. The alloy remained active and turned passive in the negative potential region. Transpassive dissolution of the alloy is observed and electropolishing is achieved in this region. The best electropolishing is obtained in 50% H3PO4 + 40% CH3COOH + 10% H2SO4. Higher content of water in the electrolytic solution is not useful for electropolishing of the alloy The experimental results also suggest that a current plateau in the transpassive potential region is not a sufficient condition to achieve electropolishing. 相似文献
42.
43.
The physicochemical and functional properties of convection oven- and freeze-dried gluten meals of two corn varieties were evaluated. The physicochemical properties (water solubility index, water absorption index, Hunter color parameters, and bulk density) and functional properties (water absorption, oil absorption, least gelation concentration, protein solubility, and emulsification properties) of convection-oven and freeze-dried corn gluten meals were compared with each other and soy flour. Freeze-dried corn gluten meals was observed to have lower bulk density (0.244-0.263 kg/m3) and was lighter in color (high L and ΔE) compared to their counterpart convection oven-dried gluten meals. Freeze-dried gluten meals from both corn varieties showed significantly higher oil absorption, water absorption, pH, emulsification, and protein solubility compared to oven-dried corn gluten meals. The gluten meals from both corn varieties had lower water absorption and bulk density but higher oil absorption than soy flour, suggesting the hydrophobic nature of corn proteins. Corn gluten meals formed thin (pourable) emulsions compared to soy flour emulsions, which were thick salad dressing type. Freeze- and convection oven-dried corn gluten meals showed significantly lower protein solubility measured at different pH than soy flour. 相似文献
44.
45.
Dielectric relaxation behaviour of (1 − x)PMN − xPZ, for x = 0.10, 0.30 and 0.40 have been studied. The nature of relaxational behaviour was found to change with PZ concentration.
A crossover from a static freezing to critical slowing down like behaviour is observed with increase in Zr4+ concentration. We have used Glazounov and Tangastev criterion to distinguish freezing and critical slowing down like behaviour. 相似文献
46.
47.
To convey the dynamic information related to traffic conditions in various parts of a city, we propose an environment utilizing the technology of smart phones to provide information anywhere and anytime. Called ";The Interactive Traffic Beat Project,"; it uses a Web-based service to deliver this information to people through their cell phones at the right time so that valuable time can be saved and the chaos on the roads can be managed. 相似文献
48.
Lean philosophy: implementation in a forging company 总被引:2,自引:2,他引:0
Ajit Kumar Sahoo N. K. Singh Ravi Shankar M. K. Tiwari 《The International Journal of Advanced Manufacturing Technology》2008,36(5-6):451-462
This research addresses the implementation of lean philosophy in a forging company with a focus on radial forging production
flow lines. Here, the prime motive is to evolve and test several strategies to eliminate waste on the shop floor. In this
research, a systematic approach is suggested for the implementation of lean principles. This paper describes an application
of value stream mapping (VSM). Consequently, the present and future states of value stream maps are constructed to improve
the production process by identifying waste and its sources. Furthermore, Taguchi’s method of design of experiments is pursued
here to minimize the forging defects produced due to imperfect operating conditions. A noticeable reduction in set-up time
and work-in-process (WIP) inventory level is substantiated. Finally, we conclude with a discussion of managerial implications
and the future scope of research. 相似文献
49.
María J. Martín David E. Singh J. Carlos Mourio Francisco F. Rivera Ramn Doallo Javier D. Bruguera 《Parallel Computing》2003,29(11-12):1763
The aim of this work is to provide a high performance air quality simulation using the STEM-II (Sulphur Transport Eulerian Model 2) program, a large-scale pollution modeling application. First, we optimize the sequential program with the aim of increasing data locality. Then, we parallelized the program using OpenMP directives for shared memory systems, and the MPI library for distributed memory machines. Performance results are presented for a SGI O2000 multiprocessor, a Fujitsu AP3000 multicomputer and a Cluster of PCs. Experimental results show that the parallel versions of the code achieve important reductions in the CPU time needed by each simulation. This will allow us to obtain results with adequate speed and reliability for the industrial environment where it is intended to be applied. 相似文献
50.