全文获取类型
收费全文 | 280568篇 |
免费 | 20754篇 |
国内免费 | 12220篇 |
专业分类
电工技术 | 16646篇 |
技术理论 | 5篇 |
综合类 | 18134篇 |
化学工业 | 39716篇 |
金属工艺 | 16531篇 |
机械仪表 | 16402篇 |
建筑科学 | 18830篇 |
矿业工程 | 7164篇 |
能源动力 | 6955篇 |
轻工业 | 18332篇 |
水利工程 | 6001篇 |
石油天然气 | 10590篇 |
武器工业 | 2206篇 |
无线电 | 33056篇 |
一般工业技术 | 36227篇 |
冶金工业 | 10818篇 |
原子能技术 | 2510篇 |
自动化技术 | 53419篇 |
出版年
2024年 | 1016篇 |
2023年 | 3274篇 |
2022年 | 6372篇 |
2021年 | 8796篇 |
2020年 | 6566篇 |
2019年 | 5192篇 |
2018年 | 19637篇 |
2017年 | 19668篇 |
2016年 | 15436篇 |
2015年 | 9278篇 |
2014年 | 11242篇 |
2013年 | 13220篇 |
2012年 | 18111篇 |
2011年 | 24815篇 |
2010年 | 22502篇 |
2009年 | 19098篇 |
2008年 | 19983篇 |
2007年 | 20395篇 |
2006年 | 11989篇 |
2005年 | 10673篇 |
2004年 | 7617篇 |
2003年 | 6747篇 |
2002年 | 5899篇 |
2001年 | 4822篇 |
2000年 | 4194篇 |
1999年 | 3484篇 |
1998年 | 2403篇 |
1997年 | 2003篇 |
1996年 | 1898篇 |
1995年 | 1550篇 |
1994年 | 1284篇 |
1993年 | 849篇 |
1992年 | 688篇 |
1991年 | 530篇 |
1990年 | 396篇 |
1989年 | 325篇 |
1988年 | 247篇 |
1987年 | 147篇 |
1986年 | 125篇 |
1985年 | 67篇 |
1984年 | 54篇 |
1982年 | 53篇 |
1981年 | 54篇 |
1980年 | 44篇 |
1968年 | 50篇 |
1966年 | 46篇 |
1965年 | 45篇 |
1959年 | 47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 0 毫秒
1.
2.
3.
A contact layer element for large deformations 总被引:1,自引:0,他引:1
4.
Cerebral microbleeds and cognitive decline in a hemodialysis patient: Case report and review of literature 下载免费PDF全文
Lin Li Mark Fisher Wei‐Ling Lau Hamid Moradi Alexander Cheung Gaby Thai Jason Handwerker Kamyar Kalantar‐Zadeh 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(3):E1-E7
Cerebral microbleeds (CMBs) are small hemosiderin deposits indicative of prior cerebral microscopic hemorrhage and previously thought to be clinically silent. Recent population‐based cross‐sectional studies and prospective longitudinal cohort studies have revealed association between CMB and cognitive dysfunction. In the general population, CMBs are associated with age, hypertension, and cerebral amyloid angiopathy. In the chronic kidney disease (CKD) population, diminished estimated glomerular filtration rate has been found to be an independent risk factor for CMB, raising the possibility that a uremic milieu may predispose to microbleeds. In the end‐stage renal disease (ESRD) population on hemodialysis, the incidence of microbleeds is significantly higher compared with a control group without history of CKD or stroke. We present an ESRD patient on chronic hemodialysis with a history of gradual cognitive decline and progressive CMBs. Through this case and literature review, we illustrate the need to develop detection and prediction models to treat this frequent development in ESRD patients. 相似文献
5.
6.
7.
刘伟 《信息技术与信息化》2015,(2):80-81
本文据国内矫直机的使用情况,提出完善弯辊功能,解决辊缝标定清零及运行中的问题,提升轧钢厂运行效率与产品质量。 相似文献
8.
9.
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
10.