全文获取类型
收费全文 | 7223篇 |
免费 | 772篇 |
国内免费 | 498篇 |
专业分类
电工技术 | 686篇 |
综合类 | 1288篇 |
化学工业 | 242篇 |
金属工艺 | 380篇 |
机械仪表 | 639篇 |
建筑科学 | 701篇 |
矿业工程 | 194篇 |
能源动力 | 196篇 |
轻工业 | 109篇 |
水利工程 | 137篇 |
石油天然气 | 185篇 |
武器工业 | 160篇 |
无线电 | 683篇 |
一般工业技术 | 1100篇 |
冶金工业 | 138篇 |
原子能技术 | 220篇 |
自动化技术 | 1435篇 |
出版年
2024年 | 22篇 |
2023年 | 65篇 |
2022年 | 117篇 |
2021年 | 149篇 |
2020年 | 207篇 |
2019年 | 167篇 |
2018年 | 181篇 |
2017年 | 242篇 |
2016年 | 258篇 |
2015年 | 283篇 |
2014年 | 414篇 |
2013年 | 470篇 |
2012年 | 522篇 |
2011年 | 552篇 |
2010年 | 441篇 |
2009年 | 414篇 |
2008年 | 388篇 |
2007年 | 492篇 |
2006年 | 445篇 |
2005年 | 372篇 |
2004年 | 321篇 |
2003年 | 251篇 |
2002年 | 269篇 |
2001年 | 195篇 |
2000年 | 217篇 |
1999年 | 175篇 |
1998年 | 129篇 |
1997年 | 124篇 |
1996年 | 118篇 |
1995年 | 95篇 |
1994年 | 78篇 |
1993年 | 63篇 |
1992年 | 54篇 |
1991年 | 43篇 |
1990年 | 42篇 |
1989年 | 33篇 |
1988年 | 27篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有8493条查询结果,搜索用时 0 毫秒
1.
A note on the Gauss-Jacobi quadrature formulae for singular integral equations of the second kind 总被引:1,自引:0,他引:1
A fast and efficient numerical method based on the Gauss-Jacobi quadrature is described that is suitable for solving Fredholm
singular integral equations of the second kind that are frequently encountered in fracture and contact mechanics. Here we
concentrate on the case when the unknown function is singular at both ends of the interval. Quadrature formulae involve fixed
nodal points and provide exact results for polynomials of degree 2n − 1, where n is the number of nodes. Finally, an application of the method to a plane problem involving complete contact is presented. 相似文献
2.
结合太原市向阳店桥梁板施工实例,介绍了采用先张法进行预应力桥梁板施工的过程。阐述了桥梁板的施工工艺,该工艺实现了整体张拉、整体放张,使钢绞线逐根受力均匀,施工速度快,能保证梁端的质量。指出拉杆系统的使用,降低了成本,增加了效益。 相似文献
3.
Lawrence K. Forbes Graeme C. Hocking Simon Wotherspoon 《Journal of Engineering Mathematics》2004,48(1):69-91
Rainwater can collect in a lens-shaped region within the rock of a tropical island, and may be separated from the underlying salt water by a sharp interface. This paper presents a nonlinear theory for determining the shape of this interface. The island is assumed to be saturated with rain, and provision is made for the outflow of rain-water through the sides of the island. The effect of a bore well on the shape of the interface is investigated, and the problem is solved using a spectral method. An integral-equation method is also presented for the case when the island has infinite width. 相似文献
4.
ETRⅠ-30调速器是瑞士爱舍维斯工厂生产的具有PID调节规律的电液调速器。本文对其液压控制系统作了较详细的介绍,供有关人员参考。 相似文献
5.
R. Knockaert I. Doghri Y. Marchal T. Pardoen F. Delannay 《International Journal of Fracture》1996,81(4):383-399
Double-edge notched (DENT) steel plates were pulled until complete fracture and several experimental observations were made (using profilometry and scanning electron microscopy). The essential work of fracture (EWF) model was found to be well verified. Numerical simulations—up to the maximum load only—of some experiments were performed using the finite element method (FEM), and incorporating geometric and material non-linearities (large deformation elasto-plasticity). Some experimental measurements were compared with the corresponding numerical computations and excellent agreement was found. 相似文献
6.
This paper presents a new concept for symmetric boundary element method (SBEM) applicable to 2-D steady-state and transit potential problems. Two kinds of SBEM formulations are derived. Symmetry is obtained simply through matrix manipulation, and no hypersingularity appears. Therefore, SBEM is much easier than the traditional symmetric Galerkin BEM. Compared with the traditional asymmetric BEM, the present SBEM can reduce the computational cost for time domain problems only. However, when applied to BEM/FEM coupling procedure, SBEM can reduce the computational cost for both steady-state and time domain problems. Three numerical examples are included to illustrate the effectiveness and accuracy of the present formulations. 相似文献
7.
介绍了天津天铁冶金集团有限公司炼钢厂转炉出钢口袖砖工艺的开发过程,主要工艺参数的制定,实践证明,该工艺的应用取得了良好的使用效果。 相似文献
8.
Bayesian and Dempster-Shafer fusion 总被引:3,自引:0,他引:3
The Kalman Filter is traditionally viewed as a prediction-correction filtering algorithm. In this work we show that it can
be viewed as a Bayesian fusion algorithm and derive it using Bayesian arguments. We begin with an outline of Bayes theory,
using it to discuss well-known quantities such as priors, likelihood and posteriors, and we provide the basic Bayesian fusion
equation. We derive the Kalman Filter from this equation using a novel method to evaluate the Chapman-Kolmogorov prediction
integral. We then use the theory to fuse data from multiple sensors. Vying with this approach is the Dempster-Shafer theory,
which deals with measures of “belief”, and is based on the nonclassical idea of “mass” as opposed to probability. Although
these two measures look very similar, there are some differences. We point them out through outlining the ideas of the Dempster-Shafer
theory and presenting the basic Dempster-Shafer fusion equation. Finally we compare the two methods, and discuss the relative
merits and demerits using an illustrative example. 相似文献
9.
北京燕山石化两巨型塔器在国内首次使用整体液压连续平移技术安装成功。该项技术可缩短工期,降低费用,提高安装的平稳性。 相似文献
10.
Allen Daniel N.; Strauss Gregory P.; Kemtes Karen A.; Goldstein Gerald 《Canadian Metallurgical Quarterly》2007,21(6):713
Hemispheric involvement in reasoning abilities has been debated for some time, and it remains unclear whether the right hemisphere's involvement in problem solving is modality specific or dependent on the type of spatial reasoning required. In the current study, 2 types of nonverbal reasoning abilities were examined, spatial reasoning and proportional reasoning, in 109 patients with cerebrovascular disease that was confined to either the right or the left hemisphere or was diffuse in nature. Results indicated that no lateralizing effects were present based on type of spatial reasoning. Findings are consistent with the suggestion that higher order cognitive processes involved in nonverbal abstraction and problem solving are not strongly lateralized to the right hemisphere but rather are more generally distributed throughout the cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献