全文获取类型
收费全文 | 37335篇 |
免费 | 3175篇 |
国内免费 | 1397篇 |
专业分类
电工技术 | 3545篇 |
技术理论 | 1篇 |
综合类 | 3040篇 |
化学工业 | 4705篇 |
金属工艺 | 1881篇 |
机械仪表 | 2099篇 |
建筑科学 | 1635篇 |
矿业工程 | 1025篇 |
能源动力 | 1164篇 |
轻工业 | 1620篇 |
水利工程 | 214篇 |
石油天然气 | 1309篇 |
武器工业 | 515篇 |
无线电 | 4990篇 |
一般工业技术 | 5353篇 |
冶金工业 | 1107篇 |
原子能技术 | 329篇 |
自动化技术 | 7375篇 |
出版年
2024年 | 144篇 |
2023年 | 583篇 |
2022年 | 823篇 |
2021年 | 781篇 |
2020年 | 873篇 |
2019年 | 923篇 |
2018年 | 712篇 |
2017年 | 1065篇 |
2016年 | 1136篇 |
2015年 | 1169篇 |
2014年 | 1526篇 |
2013年 | 1574篇 |
2012年 | 2172篇 |
2011年 | 2317篇 |
2010年 | 1548篇 |
2009年 | 1829篇 |
2008年 | 1644篇 |
2007年 | 1758篇 |
2006年 | 1560篇 |
2005年 | 1292篇 |
2004年 | 1876篇 |
2003年 | 1537篇 |
2002年 | 2045篇 |
2001年 | 1684篇 |
2000年 | 1550篇 |
1999年 | 1276篇 |
1998年 | 803篇 |
1997年 | 833篇 |
1996年 | 1707篇 |
1995年 | 975篇 |
1994年 | 714篇 |
1993年 | 235篇 |
1992年 | 197篇 |
1991年 | 199篇 |
1990年 | 183篇 |
1989年 | 112篇 |
1988年 | 84篇 |
1987年 | 55篇 |
1986年 | 70篇 |
1985年 | 83篇 |
1984年 | 57篇 |
1983年 | 44篇 |
1982年 | 43篇 |
1981年 | 34篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
超低频电磁发射机是管道内装置跟踪定位的典型常用设备,其发射磁场强度决定的有效接收距离是该类设备最重要的性能参数之一,而发射天线线圈参数对发射磁场强度有决定性影响.在已有的电池、磁芯和允许体积条件下,通过理论计算有效发射磁场强度与线圈参数的关系,得出采用双线绕法能成倍地提高有效发射磁场强度,改善穿透距离性能的结论,并以实验验证了该优化方案的有效性. 相似文献
993.
摘 要:前列腺癌近距离放射治疗是有效治疗前列腺癌的一种微创治疗方法。然而在手术针向前列腺内部植入放射性粒子的过程中,前列腺和周围软组织器官的变形会导致粒子植入偏差。本文运用计算机图像处理与有限元仿真技术,使用患者术前的核磁图像,结合盆腔解剖学知识和三维重建技术,建立前列腺器官群有限元模型,并对粒子植入手术过程进行术前的有限元模拟计算,从而得到目标位置的变形量。有限元计算中的输入量均由实验数据结合有限元软件反求获得。结果表明:模型的穿刺变形量符合术中前列腺变形情况,周边组织器官均能提供有效约束。文章方法可以应用于术前穿刺轨迹规划、剂量规划和手术模拟训练机。 相似文献
994.
995.
996.
Xiaojun Ban 《International journal of systems science》2016,47(15):3646-3655
In this paper, the control problem for a class of linear parameter varying (LPV) plant subject to actuator saturation is investigated. For the saturated LPV plant depending on the scheduling parameters in linear fractional transformation (LFT) fashion, a gain-scheduled output feedback controller in the LFT form is designed to guarantee the stability of the closed-loop LPV system and provide optimised disturbance/error attenuation performance. By using the congruent transformation, the synthesis condition is formulated as a convex optimisation problem in terms of a finite number of LMIs for which efficient optimisation techniques are available. The nonlinear inverted pendulum problem is employed to demonstrate the effectiveness of the proposed approach. Moreover, the comparison between our LPV saturated approach with an existing linear saturated method reveals the advantage of the LPV controller when handling nonlinear plants. 相似文献
997.
998.
Okan Tarhan Tursun Ahmet Oğuz Akyüz Aykut Erdem Erkut Erdem 《Computer Graphics Forum》2016,35(2):139-152
Reconstructing high dynamic range (HDR) images of a complex scene involving moving objects and dynamic backgrounds is prone to artifacts. A large number of methods have been proposed that attempt to alleviate these artifacts, known as HDR deghosting algorithms. Currently, the quality of these algorithms are judged by subjective evaluations, which are tedious to conduct and get quickly outdated as new algorithms are proposed on a rapid basis. In this paper, we propose an objective metric which aims to simplify this process. Our metric takes a stack of input exposures and the deghosting result and produces a set of artifact maps for different types of artifacts. These artifact maps can be combined to yield a single quality score. We performed a subjective experiment involving 52 subjects and 16 different scenes to validate the agreement of our quality scores with subjective judgements and observed a concordance of almost 80%. Our metric also enables a novel application that we call as hybrid deghosting, in which the output of different deghosting algorithms are combined to obtain a superior deghosting result. 相似文献
999.
Marcos Sandim Douglas Cedrim Luis Gustavo Nonato Paulo Pagliosa Afonso Paiva 《Computer Graphics Forum》2016,35(2):215-224
This paper presents a novel method to detect free‐surfaces on particle‐based volume representation. In contrast to most particle‐based free‐surface detection methods, which perform the surface identification based on physical and geometrical properties derived from the underlying fluid flow simulation, the proposed approach only demands the spatial location of the particles to properly recognize surface particles, avoiding even the use of kernels. Boundary particles are identified through a Hidden Point Removal (HPR) operator used for visibility test. Our method is very simple, fast, easy to implement and robust to changes in the distribution of particles, even when facing large deformation of the free‐surface. A set of comparisons against state‐of‐the‐art boundary detection methods show the effectiveness of our approach. The good performance of our method is also attested in the context of fluid flow simulation involving free‐surface, mainly when using level‐sets for rendering purposes. 相似文献
1000.
Florian Ferstl Ryoichi Ando Chris Wojtan Rüdiger Westermann Nils Thuerey 《Computer Graphics Forum》2016,35(2):225-232
The Fluid Implicit Particle method (FLIP) for liquid simulations uses particles to reduce numerical dissipation and provide important visual cues for events like complex splashes and small‐scale features near the liquid surface. Unfortunately, FLIP simulations can be computationally expensive, because they require a dense sampling of particles to fill the entire liquid volume. Furthermore, the vast majority of these FLIP particles contribute nothing to the fluid's visual appearance, especially for larger volumes of liquid. We present a method that only uses FLIP particles within a narrow band of the liquid surface, while efficiently representing the remaining inner volume on a regular grid. We show that a naïve realization of this idea introduces unstable and uncontrollable energy fluctuations, and we propose a novel coupling scheme between FLIP particles and regular grid which overcomes this problem. Our method drastically reduces the particle count and simulation times while yielding results that are nearly indistinguishable from regular FLIP simulations. Our approach is easy to integrate into any existing FLIP implementation. 相似文献