全文获取类型
收费全文 | 61109篇 |
免费 | 8545篇 |
国内免费 | 5246篇 |
专业分类
电工技术 | 11970篇 |
技术理论 | 1篇 |
综合类 | 7481篇 |
化学工业 | 6469篇 |
金属工艺 | 1526篇 |
机械仪表 | 3073篇 |
建筑科学 | 5455篇 |
矿业工程 | 1689篇 |
能源动力 | 2316篇 |
轻工业 | 1720篇 |
水利工程 | 2114篇 |
石油天然气 | 3062篇 |
武器工业 | 696篇 |
无线电 | 6367篇 |
一般工业技术 | 6340篇 |
冶金工业 | 1978篇 |
原子能技术 | 1021篇 |
自动化技术 | 11622篇 |
出版年
2024年 | 356篇 |
2023年 | 937篇 |
2022年 | 1660篇 |
2021年 | 1997篇 |
2020年 | 2431篇 |
2019年 | 2158篇 |
2018年 | 2070篇 |
2017年 | 2547篇 |
2016年 | 2650篇 |
2015年 | 2654篇 |
2014年 | 3750篇 |
2013年 | 4512篇 |
2012年 | 4509篇 |
2011年 | 4580篇 |
2010年 | 3362篇 |
2009年 | 3628篇 |
2008年 | 3558篇 |
2007年 | 4060篇 |
2006年 | 3624篇 |
2005年 | 3046篇 |
2004年 | 2633篇 |
2003年 | 2261篇 |
2002年 | 1880篇 |
2001年 | 1637篇 |
2000年 | 1480篇 |
1999年 | 1199篇 |
1998年 | 989篇 |
1997年 | 846篇 |
1996年 | 687篇 |
1995年 | 603篇 |
1994年 | 574篇 |
1993年 | 398篇 |
1992年 | 334篇 |
1991年 | 278篇 |
1990年 | 230篇 |
1989年 | 183篇 |
1988年 | 131篇 |
1987年 | 82篇 |
1986年 | 65篇 |
1985年 | 56篇 |
1984年 | 50篇 |
1983年 | 31篇 |
1982年 | 44篇 |
1981年 | 19篇 |
1980年 | 32篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1959年 | 9篇 |
1951年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Hashim A.
Hashim 《国际强度与非线性控制杂志
》2020,30(10):3848-3870
》2020,30(10):3848-3870
This paper introduces two novel nonlinear stochastic attitude estimators developed on the Special Orthogonal Group with the tracking error of the normalized Euclidean distance meeting predefined transient and steady‐state characteristics. The tracking error is confined to initially start within a predetermined large set such that the transient performance is guaranteed to obey dynamically reducing boundaries and decrease smoothly and asymptotically to the origin in probability from almost any initial condition. The proposed estimators produce accurate attitude estimates with remarkable convergence properties using measurements obtained from low‐cost inertial measurement units. The estimators proposed in continuous form are complemented by their discrete versions for the implementation purposes. The simulation results illustrate the effectiveness and robustness of the proposed estimators against uncertain measurements and large initialization error, whether in continuous or discrete form. 相似文献
2.
The activation of safety valves causes the development of flow reaction forces that have to be transferred in an adequate way via the piping to the steel structure or via the connected vessel into the foundation. If the safety valve outlet piping is connected to a blowdown system or, in case of blowing off into the atmosphere, are equipped with a T‐piece at the outlet, the stationary reaction forces are compensated completely. The transient opening process, however, develops flow reaction forces which culminate in peaks of short duration. In this article, a simple method will be proposed for the estimation of the resulting reaction forces as a function of the length of the pipe at the safety valve outlet. CFD calculations and blowdown tests executed with a full‐lift safety valve have confirmed this method on principle. Special importance is attributed to the short duration of the effect of the reaction forces which seems to have only a negligible impact on the supporting steel structure. 相似文献
3.
4.
This paper proposes an original method for obtaining analytical approximations of the invariant probability density function of multi-dimensional Hamiltonian dissipative dynamic systems under Gaussian white noise excitations, with linear non-conservative parts and nonlinear conservative parts. The method is based on an exact result and a heuristic argument. Its pertinence is attested by numerical tests. 相似文献
5.
An analysis is made of the characteristic features and problems of the optimal processing of the results of measurements in the case of a random observation function utilizing a nonlinear Kalman filter. A method is proposed for increasing the convergence domain of the filter with additional processing of measurements in the frequency domain. 相似文献
6.
7.
8.
Analysis of non-stationary electrochemical oscillations emerges utilization of the techniques allowing an observation of time evolution of their parameters such as instantaneous frequency, amplitude or frequency band. An algorithm of extraction of these parameters can be based on one of linear or quadratic time-frequency representations of oscillations record. In this paper, the authors present representatives of such transformations (Choi-Williams and Cone-shaped) originating from one of the most popular joint time-frequency energy distribution—Wigner-Ville distribution. Short introduction to the mathematics of the topic discussed is provided, then the authors present an example of application in the analysis of current oscillations of copper dissolution process. 相似文献
9.
In this work it is presented a study on the residence time distribution (RTD) of particles in a co-current pilot-plant spray dryer operated with a rotary atomization system. A nuclear technique is applied to investigate the RTD responses of spray dryers. The methodology is based on the injection of a radioisotope tracer in the feed stream followed by the monitoring of its concentration at the outlet stream. The experiments were performed during the drying of aqueous suspensions of gadolinium oxide. The RTD responses obtained experimentally presented good reproducibility, indicating that the technique applied is well suited to investigating fluid-dynamics of spray dryers. In addition to the experimental investigation, a mathematical model was used to describe the RTD experimental curves. 相似文献
10.
一种实现最佳用户检测的非线性优化神经网络 总被引:2,自引:0,他引:2
本文提出并讨论了实现码分多址(CDMA)系统上最佳多用户检测(MUD)的一种神经网络方法。该方法通过将最佳多用户检测视为非线性优化组合问题,利用神经网络能有效求解非线性优化问题的优势,导出了一种非线性优化神经网络来实现最佳多用户检测,理论分析和计算机模拟表明,所提出的神经网络具有可实时应用的动态性能和较传统方法优越得多的误码率性能和抗多址干扰的性能。 相似文献