全文获取类型
收费全文 | 21062篇 |
免费 | 1225篇 |
国内免费 | 1272篇 |
专业分类
电工技术 | 1059篇 |
技术理论 | 4篇 |
综合类 | 1620篇 |
化学工业 | 601篇 |
金属工艺 | 514篇 |
机械仪表 | 2564篇 |
建筑科学 | 1619篇 |
矿业工程 | 341篇 |
能源动力 | 751篇 |
轻工业 | 317篇 |
水利工程 | 254篇 |
石油天然气 | 370篇 |
武器工业 | 186篇 |
无线电 | 2077篇 |
一般工业技术 | 746篇 |
冶金工业 | 292篇 |
原子能技术 | 232篇 |
自动化技术 | 10012篇 |
出版年
2024年 | 22篇 |
2023年 | 98篇 |
2022年 | 182篇 |
2021年 | 249篇 |
2020年 | 244篇 |
2019年 | 186篇 |
2018年 | 239篇 |
2017年 | 267篇 |
2016年 | 357篇 |
2015年 | 466篇 |
2014年 | 1120篇 |
2013年 | 1004篇 |
2012年 | 1368篇 |
2011年 | 1778篇 |
2010年 | 1280篇 |
2009年 | 1188篇 |
2008年 | 1323篇 |
2007年 | 1617篇 |
2006年 | 1557篇 |
2005年 | 1440篇 |
2004年 | 1221篇 |
2003年 | 1180篇 |
2002年 | 1044篇 |
2001年 | 735篇 |
2000年 | 577篇 |
1999年 | 541篇 |
1998年 | 448篇 |
1997年 | 351篇 |
1996年 | 307篇 |
1995年 | 229篇 |
1994年 | 179篇 |
1993年 | 169篇 |
1992年 | 131篇 |
1991年 | 108篇 |
1990年 | 57篇 |
1989年 | 71篇 |
1988年 | 54篇 |
1987年 | 28篇 |
1986年 | 14篇 |
1985年 | 26篇 |
1984年 | 22篇 |
1983年 | 24篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 3篇 |
1971年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
131.
132.
双目传感器结构优化设计 总被引:9,自引:3,他引:6
综合分析了摄象机摆放姿态与双目传器有效视场的关系,同以往简单分析方法不同,文中全面分析了各种情况不同结构参数对传感器精度的影响,介绍了摄象机标定及传感器结构参数获取的方法,实验数据表明,上述分析正确,测量结果令人满意。 相似文献
133.
Gintautas Dundulis Eugenijus Uspuras Ronald F. Kulak Algirdas Marchertas 《Nuclear Engineering and Design》2007,237(8):848-857
Stress corrosion cracks have been discovered in Group Distribution Headers (GDH) at the Ignalina and Chernobyl Nuclear Power Plants. This increases the probability that a guillotine pipe break can occur that creates a whipping pipe (GDH) with the potential to damage surrounding structures—i.e. adjacent GDH and its attached piping or adjacent reinforced concrete compartment wall. The GDH is the most important component for reactor safety in case of an accident. Emergency Core Cooling System (ECCS) piping is connected to the GDH piping such that, during an accident, coolant passes from the ECSS into the GDH.Presented in this paper is the transient analysis of a Group Distribution Header following a guillotine break at the blind end of the header. Using a very conservative force loading function, the transient response of a whipping RBMK-1500 GDH along with neighboring concrete walls and pipelines is obtained using finite element methodology.The results of the study, assuming that the impacted GDH does not suffer stress corrosion cracking, indicate that the structural integrity of the compartment should be maintained and failure should not propagate from GDH to GDH. 相似文献
134.
We present a new post processing method of simulating depth of field based on accurate calculations of circles of confusion. Compared to previous work, our method derives actual scene depth information directly from the existing depth buffer, requires no specialized rendering passes, and allows easy integration into existing rendering applications. Our implementation uses an adaptive, two‐pass filter, producing a high quality depth of field effect that can be executed entirely on the GPU, taking advantage of the parallelism of modern graphics cards and permitting real time performance when applied to large numbers of pixels. 相似文献
135.
136.
Generalized adaptive notch filters with frequency debiasing for tracking of polynomial phase systems
Generalized adaptive notch filters are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. For general patterns of frequency variation the generalized adaptive notch filtering algorithms yield biased frequency estimates. We show that when system frequencies change slowly in a smooth way, the estimation bias can be substantially reduced by means of post-filtering of the frequency estimates. The modified (debiased) algorithm has better tracking capabilities than the original algorithm. 相似文献
137.
目前制糖工艺流程基本是手动控制或半自动化控制,极少数企业采用DCS系统进行集中控制,特别是应用于“一线液化两线糖化”的制糖生产工艺流程中。从实际的生产应用中介绍“两次液化-两次加酶”法生产淀粉糖生产工艺、自动化控制系统的原理、JX-300 DCS系统简述、DCS系统构成和系统组态、系统调试,重点捕述“一线液化两线糖化系统”在DCS上的具体实现。通过近五年的运行,该系统控制方案是可行的,工艺运行稳定可靠,完全满足工艺的要求。 相似文献
138.
139.
D. J. Lee 《Chemical Engineering Communications》1995,136(1):13-25
The nonlinear dynamic behaviour relating the wet front size and liquid saturation under inner cylinder (or rectangular cell) in cylindrical (or rectangular) capillary suction apparatus was investigated. The slow manifold explanation was proposed and the fast- and slow-varying variables were identified. Experiments were conducted to verify theoretical findings. 相似文献
140.
Young-Jin Kim Jin-Ho Son Hae-Dong Chung Joon-Gu Kim 《Journal of Mechanical Science and Technology》1994,8(2):198-205
This paper describes the development strategy of a prototype expert system, called RViES, for the reactor vessel integrity.
The main objectives of the system are to assist engineers to perform fatigue and fracture mechanics analyses of reactor vessels
quickly and accurately. The system consists of three parts; user interface, knowledge base and inference engine. Various rules
recommended in codes and standards are stored in the knowledge base. Several case studies were performed to check the usefulness
of the system. 相似文献