全文获取类型
收费全文 | 1453篇 |
免费 | 59篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 16篇 |
综合类 | 5篇 |
化学工业 | 353篇 |
金属工艺 | 26篇 |
机械仪表 | 35篇 |
建筑科学 | 22篇 |
能源动力 | 86篇 |
轻工业 | 95篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
无线电 | 182篇 |
一般工业技术 | 299篇 |
冶金工业 | 167篇 |
原子能技术 | 14篇 |
自动化技术 | 207篇 |
出版年
2023年 | 23篇 |
2022年 | 51篇 |
2021年 | 52篇 |
2020年 | 53篇 |
2019年 | 48篇 |
2018年 | 69篇 |
2017年 | 56篇 |
2016年 | 65篇 |
2015年 | 31篇 |
2014年 | 44篇 |
2013年 | 136篇 |
2012年 | 59篇 |
2011年 | 61篇 |
2010年 | 63篇 |
2009年 | 61篇 |
2008年 | 38篇 |
2007年 | 38篇 |
2006年 | 47篇 |
2005年 | 26篇 |
2004年 | 24篇 |
2003年 | 25篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 21篇 |
1999年 | 17篇 |
1998年 | 38篇 |
1997年 | 24篇 |
1996年 | 38篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 23篇 |
1992年 | 18篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 17篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1975年 | 7篇 |
1974年 | 5篇 |
排序方式: 共有1513条查询结果,搜索用时 31 毫秒
31.
Varsha Daftardar-Gejji Sachin Bhalekar 《Computers & Mathematics with Applications》2010,59(3):1117-1127
Present paper deals with fractional version of a dynamical system introduced by C. Liu, L. Liu and T. Liu [C. Liu, L. Liu, T. Liu, A novel three-dimensional autonomous chaos system, Chaos Solitons Fractals 39 (4) (2009) 1950–1958]. Numerical investigations on the dynamics of this system have been carried out. Properties of the system have been analyzed by means of Lyapunov exponents. Furthermore the minimum effective dimensions have been identified for chaos to exist in commensurate and incommensurate orders. It is noteworthy that the results obtained are consistent with the analytical conditions given in the literature. 相似文献
32.
This work provides a framework for nominal and robust stability analysis for a class of discrete-time nonlinear recursive observers (DNRO). Given that the system has linear output mapping, local observability and Jacobian matrices satisfying certain conditions, the nominal and robust stability of the DNRO is defined by the property of estimation error dynamics and is analyzed using Lyapunov theory. Moreover, a simultaneous state and parameter estimation scheme is shown to be Input-to-State Stable (ISS), and adaptively reduce plant-model mismatch on-line. Three design strategies of the DNRO that satisfy the stability results are given as examples, including the widely used extended Kalman filter, extended Luenberger observer, and the fixed gain observer. 相似文献
33.
A key issue that needs to be addressed while performing fault diagnosis using black box models is that of robustness against abrupt changes in unknown inputs. A fundamental difficulty with the robust FDI design approaches available in the literature is that they require some a priori knowledge of the model for unmeasured disturbances or modeling uncertainty. In this work, we propose a novel approach for modeling abrupt changes in unmeasured disturbances when innovation form of state space model (i.e. black box observer) is used for fault diagnosis. A disturbance coupling matrix is developed using singular value decomposition of the extended observability matrix and further used to formulate a robust fault diagnosis scheme based on generalized likelihood ratio test. The proposed modeling approach does not require any a priori knowledge of how these faults affect the system dynamics. To isolate sensor and actuator biases from step jumps in unmeasured disturbances, a statistically rigorous method is developed for distinguishing between faults modeled using different number of parameters. Simulation studies on a heavy oil fractionator example show that the proposed FDI methodology based on identified models can be used to effectively distinguish between sensor biases, actuator biases and other soft faults caused by changes in unmeasured disturbance variables. The fault tolerant control scheme, which makes use of the proposed robust FDI methodology, gives significantly better control performance than conventional controllers when soft faults occur. The experimental evaluation of the proposed FDI methodology on a laboratory scale stirred tank temperature control set-up corroborates these conclusions. 相似文献
34.
This work deals with state estimation and process control for nonlinear systems, especially when nonlinear model predictive control (NMPC) is integrated with extended Kalman filter (EKF) as the state estimator. In particular, we focus on the robust stability of NMPC and EKF in the presence of plant-model mismatch. The convergence property of the estimation error from the EKF in the presence of non-vanishing perturbations is established based on our previous work [1]. In addition, a so-called one way interaction is shown that the EKF error is not influenced by control action from the NMPC. Hence, the EKF analysis is still valid in the output-feedback NMPC framework, even though there is no separation principle for general nonlinear systems. With this result, we study the robust stability of the output-feedback NMPC under the impact of the estimation error. It turns out the output-feedback NMPC with EKF is Input-to-State practical Stable (ISpS). Finally, two offset-free strategies of output-feedback NMPC are presented and illustrated through a simulation example. 相似文献
35.
Ketan P. Detroja Ravindra D. Gudi Sachin C. Patwardhan 《Control Engineering Practice》2012,20(10):1033-1041
Historical data based fault diagnosis methods exploit two key strengths of multivariate statistical approaches, viz.: (i) data compression ability, and (ii) discriminatory ability. It has been shown that correspondence analysis (CA) is superior to principal components analysis (PCA) on both these counts (Detroja, Gudi, Patwardhan, & Roy, 2006a), and hence is more suited for the task of fault detection and isolation (FDI). In this paper, we propose a CA based methodology for fault diagnosis that can facilitate significant data reduction as well as better discrimination. The proposed methodology is based on the principle of distributional equivalence (PDE). The PDE is a property unique to the CA algorithm and can be very useful in analyzing large datasets. The principle, when applied to historical data sets for FDI, can significantly reduce the data matrix size without significantly affecting the discriminatory ability of the CA algorithm. This can significantly reduce computational load during statistical model building. The data reduction ability of the proposed methodology is demonstrated using a simulation case study involving benchmark quadruple tank laboratory process. The proposed methodology when applied to experimental data obtained from the quadruple tank process also demonstrated data reduction capabilities of the principle of distributional equivalence. The above aspect has also been validated for large-scale data sets using the benchmark Tennessee Eastman process simulation case study. 相似文献
36.
Low Cycle Fatigue (LCF) on smooth hour glass specimens and Fatigue Crack Propagation (FCP) studies on Single Edge Notch (SEN) specimens were carried out at room temperature on four Cu-Al polycrystalline alloys to investigate the effects of Stacking Fault Energy (SFE) and mechanical property variations on fatigue characteristics. Significant improvements in fatigue properties were observed for alloys of low SFE. A microhardness technique was used to delineate the fatigue plastic zone ahead of stopped cracks at several stress intensity ranges for all the alloys. Planar slip was associated with a less than a second power dependence of plastic zone size on the stress intensity range. Transmission Electron Microscopy (TEM) was used to observe the substructures that developed both in LCF at different strain ranges and also ahead of fatigue cracks at different stress intensity ranges. Fractography was carried out to study the micromechanisms of crack propagation using a two stage replication technique. The experimental results were in good agreement with a theoretical model for FCP developed previously by the authors which incorporates mechanical and microstructural variables. 相似文献
37.
Title of program: REDUCED TENSOR MATRIX ELEMENTS 2 Catalogue number: AAKP Program obtainable from: CPC Program Library, Queen's University of Belfast N. Ireland (see application form in this issue) Computer: Installation: IBM 360/75 University of Waterloo, Waterloo, Ont. Canada Operating system: OS/360 HASP II Programming languages used: FORTRAN IV High speed store required: 102 K bytes No. of bits per byte: 8 Overlay structure: None Other peripherals used: Card reader, line printer No. of cards in combined program and test deck: 1524 Card punching code: EBCDIC 029CPC Library subprograms used:
Cat. numbers | Titles | Refs. in C.P.C. |
ACQB | P SHELL CFP | 1 (1969) 15 |
ACRN | A NEW D SHELL CFP | 6 (1973) 88 |
AAGD | NJSYM | 1 (1970) 241, 2 (1971) 173 |
AAGD0001 | ADAPT NJSYM FOR WEIGHTS | 2 (1971) 180 |
AAGD0002 | ADAPT TO INTEGER ARITHMETIC | 5 (1973) 161 |