全文获取类型
收费全文 | 961篇 |
免费 | 45篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 11篇 |
综合类 | 1篇 |
化学工业 | 219篇 |
金属工艺 | 9篇 |
机械仪表 | 34篇 |
建筑科学 | 72篇 |
矿业工程 | 1篇 |
能源动力 | 35篇 |
轻工业 | 68篇 |
水利工程 | 4篇 |
无线电 | 78篇 |
一般工业技术 | 182篇 |
冶金工业 | 141篇 |
原子能技术 | 7篇 |
自动化技术 | 145篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 17篇 |
2020年 | 15篇 |
2019年 | 25篇 |
2018年 | 20篇 |
2017年 | 15篇 |
2016年 | 27篇 |
2015年 | 27篇 |
2014年 | 45篇 |
2013年 | 85篇 |
2012年 | 54篇 |
2011年 | 69篇 |
2010年 | 45篇 |
2009年 | 48篇 |
2008年 | 42篇 |
2007年 | 38篇 |
2006年 | 30篇 |
2005年 | 36篇 |
2004年 | 30篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 54篇 |
1997年 | 25篇 |
1996年 | 14篇 |
1995年 | 17篇 |
1994年 | 14篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1961年 | 1篇 |
1960年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有1007条查询结果,搜索用时 15 毫秒
1.
Gökelma Mertol Einarsrud Kristian Etienne Tranell Gabriella Friedrich Bernd 《Metallurgical and Materials Transactions B》2020,51(2):850-860
Metallurgical and Materials Transactions B - The quality requirements of aluminum products are steadily increasing, and the presence of non-metallic inclusions have a large impact on the quality of... 相似文献
2.
DNA double-strand breaks are very genotoxic lesions that can result in chromosome aberrations. The current view is that DNA double-strand breaks are repaired most efficiently through homologous recombination in yeast and simple end-joining in mammalian cells. However, recent experiments reveal that both repair pathways are conserved from yeast to mammals, including humans. The challenge ahead is to put the different pieces of the jigsaw together into coherent mechanisms for both pathways and to determine their relative contributions to ionizing-radiation resistance and to the prevention of genetic instability and carcinogenesis. 相似文献
3.
M. Quecedo M. Pastor M. I. Herreros J. A. Fernndez Merodo 《International journal for numerical methods in engineering》2004,59(6):755-794
This paper proposes a two‐dimensional (2D) model for the analysis of the propagation of fast landslides involving a fluidized material such as debris and mud flows, flowslides and avalanching flows. The model is based on the Navier–Stokes depth‐integrated equations. To incorporate the effect of steep slopes and centrifugal forces due to the high velocities characterizing the flowslides and the bed curvature, a curvilinear system of reference is used. The corresponding equations of motion are complemented by depth‐averaged constitutive equations and bed friction laws. The resulting set of differential equations are solved using the two‐step Taylor–Galerkin algorithm. This algorithm has been used by the authors to solve hydraulic and dam‐break problems using the finite element method. Owing to the importance of the source term compared to the advection component, the proposed algorithm follows a splitting scheme using a fourth‐order Runge–Kutta method for integrating the friction and slope components. The performance of the overall approach has been checked in a number of examples. The analysis of the results provides insights into the key elements of the model and shows the adequacy of the method to solve real problems where merging and splitting of the flow occur. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
4.
Summary The potential of the micro-Fourier Transform Raman tool in examining specific localized regions in polymeric materials with some degree of fluorescence when analyzed by conventional Raman spectroscopy is examined. Analysis of characteristic bands of the vibrational spectra obtained in a small area damaged by a visible and NIR laser beam in commercial Polyethylene Terephthalate (PET) shows a different conformer ratio than that observed in a non irradiated zone. 相似文献
5.
Abstract: Environmental justice advocates have recently focused attention on cumulative exposure in minority neighborhoods due to multiple sources of pollution. This article uses U.S. EPA's National Air Toxics Assessment (NATA) for 1996 to examine environmental inequality in California, a state that has been a recent innovator in environmental justice policy. We first estimate potential lifetime cancer risks from mobile and stationary sources. We then consider the distribution of these risks using both simple comparisons and a multivariate model in which we control for income, land use, and other explanatory factors, as well as spatial correlation. We find large racial disparities in California's “riskscape” as well as inequalities by other factors and suggest several implications for environmental and land use policy. 相似文献
6.
7.
8.
The residual deformation produced by Vickers microindentations in poly(3,3-dimethyl oxetane) (PDMO) was analysed by Raman microspectroscopy. Microstructural variations were observed as the Raman spectra were recorded at different positions along and out of the microindentation. A gradual distribution of the monoclinic and orthorhombic structures arises as the spectra were scanned from the centre to the edge of the impression area. This crystalline variation in PDMO, which reflects the degree of stress present on the surface of the sample, was utilized to obtain information on the distribution of pressure in and around the microindentation. In addition to the clear variation of pressure inside the permanently deformed region, no crystalline transformation was noted out of the impression area. Similar features were observed when the Raman spectra were recorded along one of the diagonals of the indentation. 相似文献
9.
Analytical and numerical analysis of phase and amplitude errors in the performance of arrayed waveguide gratings 总被引:1,自引:0,他引:1
Munoz P. Pastor D. Capmany J. Sales S. 《IEEE journal of selected topics in quantum electronics》2002,8(6):1130-1141
The closed expression of the mean power transfer function for an arrayed waveguide grating (AWG), taking into account fabrication errors, is presented. Comparison with numerical simulations using a previous Fourier optics modeling show good agreement. The procedure to predict the AWG floor level using the numerical modeling is presented and checked against the analytical derived expressions. 相似文献
10.
George Chryssolouris James E. Pierce Kristian Dicke 《International Journal of Flexible Manufacturing Systems》1992,4(3-4):309-330
This paper introduces a generic decision-making framework for assigning resources of a manufacturing system to production tasks. Resources are broadly defined production units, such as machines, human operators, or material handling vehicles; and tasks are activities performed by resources. In the specific context of FMS, resources correspond to individual machines; tasks correspond to operations to be performed on parts. The framework assumes a hierarchical structure of the system and calls for the execution of four consecutive steps to make a decision for the assignment of a resource to a task. These steps are 1) establishment of decision-making criteria, 2) formation of alternative assignments, 3) estimation of the consequences of the assignments, and 4) selection of the best alternative assignment. This framework has been applied to an existing FMS as an operational policy that decides what task will be executed on which resource of this FMS. Simulation runs provide some initial results of the application of this policy. It is shown that the policy provides flexibility in terms of system performance and computational effort. 相似文献