全文获取类型
收费全文 | 2748篇 |
免费 | 92篇 |
国内免费 | 17篇 |
专业分类
电工技术 | 131篇 |
综合类 | 3篇 |
化学工业 | 357篇 |
金属工艺 | 73篇 |
机械仪表 | 50篇 |
建筑科学 | 147篇 |
矿业工程 | 10篇 |
能源动力 | 92篇 |
轻工业 | 260篇 |
水利工程 | 18篇 |
石油天然气 | 13篇 |
武器工业 | 1篇 |
无线电 | 303篇 |
一般工业技术 | 322篇 |
冶金工业 | 347篇 |
原子能技术 | 17篇 |
自动化技术 | 713篇 |
出版年
2023年 | 12篇 |
2022年 | 29篇 |
2021年 | 44篇 |
2020年 | 24篇 |
2019年 | 44篇 |
2018年 | 86篇 |
2017年 | 59篇 |
2016年 | 52篇 |
2015年 | 47篇 |
2014年 | 93篇 |
2013年 | 201篇 |
2012年 | 171篇 |
2011年 | 141篇 |
2010年 | 176篇 |
2009年 | 181篇 |
2008年 | 210篇 |
2007年 | 136篇 |
2006年 | 159篇 |
2005年 | 140篇 |
2004年 | 78篇 |
2003年 | 98篇 |
2002年 | 84篇 |
2001年 | 42篇 |
2000年 | 56篇 |
1999年 | 54篇 |
1998年 | 49篇 |
1997年 | 39篇 |
1996年 | 33篇 |
1995年 | 37篇 |
1994年 | 22篇 |
1993年 | 26篇 |
1992年 | 24篇 |
1991年 | 17篇 |
1990年 | 19篇 |
1989年 | 20篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 13篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1942年 | 3篇 |
1940年 | 3篇 |
排序方式: 共有2857条查询结果,搜索用时 0 毫秒
1.
2.
Steve Brightman 《今日电子》2008,(12)
采用WiMedia UWB标准的越来越多
WiMedia通用无线电平台是实现传输速率高达480Mb/s(更高的传输速率正在开发中)无线个人局域网(WPAN)的基础。这个平台并不局限于某一类应用,而是允许同时存在不同的协议适配层,如图1所示。WiMedia规范既规定了一些如无线USB之间相互通信的应用,也规定其他不相互通信的接口同时存在的应用。 相似文献
3.
4.
Amit Chourasia Steve Cutchin Yifeng Cui Reagan W Moore Kim Olsen Steven M Day J Bernard Minster Philip Maechling Thomas H Jordan 《Computer Graphics and Applications, IEEE》2007,27(5):28-34
This study focuses on the visualization of a series of large earthquake simulations collectively called TeraShake. The simulation series aims to assess the impact of San Andreas Fault earthquake scenarios in Southern California. We discuss the role of visualization in gaining scientific insight and aiding unexpected discoveries. 相似文献
5.
Steve Lord 《Network Security》2003,2003(1):10-12
GSM is a series of standards defining various aspects of mobile voice and data communications. These standards provide a framework that looks set to underlie modern mobile business communications well into the 21st century. 相似文献
6.
Olivier Klein Steve Donovan Martin Dressel George Grüner 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(12):2423-2457
This report reviews the analysis used to extract the complex conductivity of a compound from a microwave cavity perturbation measurement. We intend to present a generalized treatment valid for any spheroidally shaped sample of arbitrary conductivity which is placed at either the electric or magnetic field antinode of the cavity. To begin with, we establish the relationship between the measured parameters and the conductivity for a spherical sample. Next, we extend these results to the case of spheroids; and for the first time, we cover all different configurations that one can possibly use to study an arbitrary conducting sample inside a cavity: in particular, all possible orientations of the sample with respect to the applied field are solved. 相似文献
7.
Steve Barrett 《Fuel Cells Bulletin》2003,2003(6):11-13
A new national initiative, Fuel Cells UK, has been established to act as a focus for the development of a fuel cell industry in Britain, and to liaise and partner more effectively with national and regional initiatives around the world. The first step is to create a ‘unified vision’ for the UK fuel cell sector, for both the short term and the long term, to guide industry, academia and government on the way to a world-class fuel cell industry. 相似文献
8.
Alpass Fiona; Flett Ross; Humphries Steve; Massey Claire; Morriss Stuart; Long Nigel 《Canadian Metallurgical Quarterly》2004,11(3):270
Previous studies have identified a number of different farm stressors and have reported gender and age differences in levels of stress. This study aimed to determine stress experienced by New Zealand dairy farmers, particularly in relation to adoption of new technology and its relationship to age and gender. Measures of farm stress and adoption of technology were completed by 985 dairy farmers. The highest levels of stress were reported for time pressures, machinery breakdown, weather, and government policies. Stress related to new technologies occurred rarely. Women reported more stress and higher levels of stress for understanding new technologies. There was also an increase in severity of stress with age related to new technologies. Overall, stress levels were moderate and may reflect favorable economic conditions. The findings suggest a need to tailor stress interventions to meet specific needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Data collection, both automatic and manual, lies at the heart of all empirical studies. The quality of data collected from
software informs decisions on maintenance, testing and wider issues such as the need for system re-engineering. While of the
two types stated, automatic data collection is preferable, there are numerous occasions when manual data collection is unavoidable.
Yet, very little evidence exists to assess the error-proneness of the latter. Herein, we investigate the extent to which manual
data collection for Java software compared with its automatic counterpart for the same data. We investigate three hypotheses
relating to the difference between automated and manual data collection. Five Java systems were used to support our investigation.
Results showed that, as expected, manual data collection was error-prone, but nowhere near the extent we had initially envisaged.
Key indicators of mistakes in manual data collection were found to be poor developer coding style, poor adherence to sound
OO coding principles, and the existence of relatively large classes in some systems. Some interesting results were found relating
to the collection of public class features and the types of error made during manual data collection. The study thus offers
an insight into some of the typical problems associated with collecting data manually; more significantly, it highlights the
problems that poorly written systems have on the quality of visually extracted data. 相似文献
10.
Distributed active storage architectures are designed to offload user-level processing to the peripheral from the host servers.
In this paper, we report preliminary investigation on performance and fault recovery designs, as impacted by emerging storage
interconnect protocols and state-of-the-art storage devices. Empirical results obtained using validated device-level and interconnect
data demonstrate the significance of the said parameters on the overall system performance and reliability. 相似文献