全文获取类型
收费全文 | 34843篇 |
免费 | 3776篇 |
国内免费 | 1953篇 |
专业分类
电工技术 | 5297篇 |
技术理论 | 4篇 |
综合类 | 2785篇 |
化学工业 | 1456篇 |
金属工艺 | 768篇 |
机械仪表 | 2660篇 |
建筑科学 | 4074篇 |
矿业工程 | 2726篇 |
能源动力 | 898篇 |
轻工业 | 775篇 |
水利工程 | 3123篇 |
石油天然气 | 912篇 |
武器工业 | 243篇 |
无线电 | 3805篇 |
一般工业技术 | 1771篇 |
冶金工业 | 787篇 |
原子能技术 | 495篇 |
自动化技术 | 7993篇 |
出版年
2024年 | 169篇 |
2023年 | 491篇 |
2022年 | 1000篇 |
2021年 | 1233篇 |
2020年 | 1273篇 |
2019年 | 912篇 |
2018年 | 844篇 |
2017年 | 1146篇 |
2016年 | 1388篇 |
2015年 | 1648篇 |
2014年 | 2871篇 |
2013年 | 2471篇 |
2012年 | 3462篇 |
2011年 | 3368篇 |
2010年 | 2234篇 |
2009年 | 2127篇 |
2008年 | 1895篇 |
2007年 | 2123篇 |
2006年 | 1852篇 |
2005年 | 1662篇 |
2004年 | 1420篇 |
2003年 | 1136篇 |
2002年 | 879篇 |
2001年 | 649篇 |
2000年 | 540篇 |
1999年 | 409篇 |
1998年 | 304篇 |
1997年 | 248篇 |
1996年 | 200篇 |
1995年 | 149篇 |
1994年 | 117篇 |
1993年 | 71篇 |
1992年 | 51篇 |
1991年 | 46篇 |
1990年 | 29篇 |
1989年 | 31篇 |
1988年 | 21篇 |
1987年 | 6篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1963年 | 4篇 |
1962年 | 3篇 |
1961年 | 2篇 |
1960年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
51.
本文介绍了新丰江大坝监测自动化系统从失败走向成功的实施过程,强调了良好的工作环境以及精心的现场维护在大坝监测自动化应用中的重要性。 相似文献
52.
提出用表征大型机械系统健康状态的相对劣化度作为监控机械磨损状态和油品质量变化的综合判断指标,以便结合反映机器工作状态的其它因素,共同评定机器的健康状态。以柴油机为例,对监测得到的柴油机润滑油的铁谱参数、磨损金属元素含量和油品理化性能等数据进行综合分析和处理,所得相对劣化度的变化趋势,较准确地反映了柴油机的工作状况。该方法不仅简单实用,而且便于将油液监测技术与其他监测技术(如振动诊断技术)结合起来,用一统一指标描述机器的健康状况,达到监测和预报的目的,为开发基于多种监测技术的智能诊断系统打下基础。 相似文献
53.
A damage identification technique for CF/EP composite laminates using distributed piezoelectric transducers 总被引:8,自引:0,他引:8
In this study, a damage identification approach was developed for carbon fibre/epoxy composite laminates with localized internal delamination. Propagation of the Lamb wave in laminates and its interaction with the delamination were examined. The fundamental symmetric Lamb wave mode, S0, and the lowest order shear wave mode, S0′, were chosen to predict damage location. A real-time active diagnosis system was therefore established. This technique uses distributed piezoelectric transducers to generate and monitor the ultrasonic Lamb wave with narrowband frequency. The two-way switches were employed to minimize the number of transducers. A signal-processing scheme based on the time–frequency spectrographic analysis was utilised to extract useful diagnostic information. Also, an optimal identification method was applied on damage searching procedure to reduce errors and obtain the diagnostic results promptly. Experiments were conducted on [0/−45/45/90]s CF/EP laminates to verify this diagnosis system. The results obtained show that satisfactory detection accuracy could be achieved. 相似文献
54.
Zheng Wen Technological Faculty of Maintenance Engineering Guangzhou University Guangzhou P.R.China 《国际设备工程与管理》1997,(3)
VibrationMonitoringandDiagnosisofPipelinePumpsonOfshorePlatformsZhengWenTechnologicalFacultyofMaintenanceEngineringGuangzhou... 相似文献
55.
A vibration-acoustic method for diagnostics and monitoring of production processes such as cutting metals makes it possible
compared with other methods to reduce the requirement for measuring equipment and it provides a computer representation of
the results observed. The set of equipment suggested has low cost and it exhibits considerable flexibility compared with existing
equipment.
__________
Translated from Izmeritel’naya Tekhnika, No. 7, pp. 30–34, July, 2006. 相似文献
56.
We propose in this paper a self-organized monitoring architecture for mobile ad-hoc networks based on a selective scheme where
subsets of nodes are managed. These nodes are determined based on their network behavior in order to favor subsets of well-connected
nodes. The key idea is to relax the requirements of the management plane, and to use these manageable subsets to monitor the
performance of the overall network. We therefore propose a new performance metric to be monitored, in order to estimate the
capability of ad-hoc nodes to communicate end-to-end in the network. Extensive simulations show how different parameters affect
this metric. 相似文献
57.
58.
Carolyn McGregor Bruce Kneale Mark Tracy 《Journal of Network and Computer Applications》2007,30(4):1309-1323
Premature and ill term babies born in regional Australia must be moved to another hospital with Neonatal Intensive Care Unit (NICU) facilities. Transferred pre-term and critically ill term babies have higher mortality rates and much higher rates of long term disability than similar babies born in hospitals with NICU facilities. This paper details the Bush Babies Broadband project that aims to significantly improve the quality of treatment for babies born in rural, remote as well as urban areas by providing the first on-demand virtual NICU architecture in Australia. Real-time data collected from medical monitors and ventilators attached to the baby, audiovisual streams and static physiological data such as X-ray images are transmitted to the consulting Neonatologist to gain a better picture of the patient's condition than is currently available. The key contribution of this significant research is the infrastructure providing a mechanism for Neonatologists to receive information directly from a regional hospital, thereby preventing, in some cases, the immediate need to move the baby. A key benefit of this framework is that it is available to link regional hospitals with the supporting NICU Neonatologist ‘on demand’ eliminating the need to establish permanent point to point connections. This paper further describes the application of that architecture to a specific pilot connecting the Bathurst regional hospital with Neonatologists within the NICU at Nepean Hospital, Penrith Australia. 相似文献
59.
60.
农业重组微生物生物安全研究进展 总被引:2,自引:2,他引:0
综述了近年来农业重组微生物的研究现状和进展 ,详细介绍农业重组微生物环境释放的监控方法以及对环境的冲击作用 ,对一些有关生物安全研究的热点问题进行了探讨 相似文献