全文获取类型
收费全文 | 666篇 |
免费 | 88篇 |
国内免费 | 40篇 |
专业分类
电工技术 | 20篇 |
综合类 | 73篇 |
化学工业 | 35篇 |
金属工艺 | 21篇 |
机械仪表 | 79篇 |
建筑科学 | 60篇 |
矿业工程 | 6篇 |
能源动力 | 14篇 |
轻工业 | 21篇 |
水利工程 | 28篇 |
石油天然气 | 11篇 |
武器工业 | 4篇 |
无线电 | 55篇 |
一般工业技术 | 256篇 |
冶金工业 | 28篇 |
原子能技术 | 9篇 |
自动化技术 | 74篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 20篇 |
2021年 | 11篇 |
2020年 | 21篇 |
2019年 | 20篇 |
2018年 | 20篇 |
2017年 | 20篇 |
2016年 | 34篇 |
2015年 | 37篇 |
2014年 | 34篇 |
2013年 | 63篇 |
2012年 | 52篇 |
2011年 | 60篇 |
2010年 | 34篇 |
2009年 | 34篇 |
2008年 | 38篇 |
2007年 | 31篇 |
2006年 | 38篇 |
2005年 | 46篇 |
2004年 | 24篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 21篇 |
1999年 | 17篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
排序方式: 共有794条查询结果,搜索用时 62 毫秒
1.
F. Baldoni 《Journal of Engineering Mathematics》1996,30(6):647-659
The mechanism of surface diffusion is taken at the basis of the phenomenon of slippage of the contact line of a liquid film. With the aid of the condition of continuity of the traction vectors at the solid-liquid interface, we obtained an evolution equation for the velocity of the fluid particles at the wall which shows a marked resemblance with Millikan's equation for the slippage coefficient of gases and reduces, in the limit of small surface diffusivity, to the classical Stokes-Einstein model. The influence of surface roughness is explicitely taken into account and, among other results, cases of absence of slip caused by the attachment of the liquid film to the solid surface and of slippage solely induced by surface roughness are found. Finally, the effect of the surface deformation upon the surface velocity of the fluid particles is examined in some detail. 相似文献
2.
3.
4.
在后工业时代,建筑设计已经冲破了西方思维所惯用的二元对立方式的约束,呈现出日新月异的景象,建筑表皮的创作尤为突出。这个住宅设计是从四维分解到四维连续的一种大胆尝试,并引入拓扑学的基本方法处理动态空间。 相似文献
5.
6.
Different materials have different coefficients of thermal expansion, which is a measure of the change in length for a given change in temperature. When different materials are combined structurally, as in a bonded joint, a temperature change leads to stresses being set up. These stresses are present even in an unloaded joint which has been cured at say 150°C and cooled to room temperature. Further stresses result from operations at even lower temperatures.
In addition to temperature-induced stresses, account also has to be taken of changes in adhesive properties. Low temperatures cause the adhesive to become more brittle (reduced strain to failure), while high temperatures cause the adhesive to become more ductile, but make it less strong and more liable to creep.
Theoretical predictions are made of the strength of a series of aluminium/CFRP joints using three different adhesives at 20°C and 55°C. Various failure criteria are used to show good correlation with experimental results. 相似文献
In addition to temperature-induced stresses, account also has to be taken of changes in adhesive properties. Low temperatures cause the adhesive to become more brittle (reduced strain to failure), while high temperatures cause the adhesive to become more ductile, but make it less strong and more liable to creep.
Theoretical predictions are made of the strength of a series of aluminium/CFRP joints using three different adhesives at 20°C and 55°C. Various failure criteria are used to show good correlation with experimental results. 相似文献
7.
Robotics has aroused huge attention since the 1950s. Irrespective of the uniqueness that industrial applications exhibit, conventional rigid robots have displayed noticeable limitations, particularly in safe cooperation as well as with environmental adaption. Accordingly, scientists have shifted their focus on soft robotics to apply this type of robots more effectively in unstructured environments. For decades, they have been committed to exploring sub-fields of soft robotics (e.g., cutting-edge techniques in design and fabrication, accurate modeling, as well as advanced control algorithms). Although scientists have made many different efforts, they share the common goal of enhancing applicability. The presented paper aims to brief the progress of soft robotic research for readers interested in this field, and clarify how an appropriate control algorithm can be produced for soft robots with specific morphologies. This paper, instead of enumerating existing modeling or control methods of a certain soft robot prototype, interprets for the relationship between morphology and morphology-dependent motion strategy, attempts to delve into the common issues in a particular class of soft robots, and elucidates a generic solution to enhance their performance. 相似文献
8.
基于独立连续变量和复合指数函数的位移约束平面连续体结构拓扑优化 总被引:1,自引:0,他引:1
为了进一步研究连续体结构拓扑优化模型的合理性和可行性,基于独立、连续、映射( independent continuous mapping,ICM)方法,在满足结构位移约束的条件下,通过引入复合指数形式过滤函数对位移约束下质量最小化( minimum weight with a displacement constraint,MWDC)模型进行了改进,建立了基于独立连续变量和复合指数函数的位移约束平面连续体结构拓扑优化模型,并进行了优化求解。同时,利用M语言,基于Matlab软件平台,开发了相应的拓扑优化计算程序,并针对4种典型平面连续体结构进行了数值验证,分别比较分析了体积约束下的柔顺度最小化( minimum compliance with a volume constraint,MCVC)模型、MWDC模型以及改进的MWDC模型所得到的最优拓扑结构。数值结果表明:采用复合指数形式过滤函数改进的MWDC优化模型迭代次数更少,优化求解计算效率更高。 相似文献
9.
The paper treats the control problem of a class of robots constituted by a chain of continuum segments. The technological model basis is a central, long and thin, highly flexible and elastic backbone. The segment control system is a decoupled one. The main parameters of the arm control are determined by the curvature and curvature gradient. The dynamic model is inferred. The primary benefit of the proposed method is that the dynamic equations are represented by a set of ODE’s in time instead of PDE’s in time and space, and the new curvature gradient lumped parameter model is used. A sliding mode control system is used in order to achieve the desired shape of the arm. The stability of the closed-loop control system is proven. Numerical simulations and an experimental platform are also provided to verify the effectiveness of the presented approach. 相似文献
10.
G.S. Chirikjian 《Advanced Robotics》2015,29(13):817-829
Hyper-redundant (or snakelike) manipulators have many more degrees of freedom than required to position and orient an object in space. They have been employed in a variety of applications ranging from search-and-rescue to minimally invasive surgical procedures, and recently they even have been proposed as solutions to problems in maintaining civil infrastructure and the repair of satellites. The kinematic and dynamic properties of snakelike robots are captured naturally using a continuum backbone curve equipped with a naturally evolving set of reference frames, stiffness properties, and mass density. When the snakelike robot has a continuum architecture, the backbone curve corresponds with the physical device itself. Interestingly, these same modeling ideas can be used to describe conformational shapes of DNA molecules and filamentous protein structures in solution and in cells. This paper reviews several classes of snakelike robots: (1) hyper-redundant manipulators guided by backbone curves; (2) flexible steerable needles; and (3) concentric tube continuum robots. It is then shown how the same mathematical modeling methods used in these robotics contexts can be used to model molecules such as DNA. All of these problems are treated in the context of a common mathematical framework based on the differential geometry of curves, continuum mechanics, and variational calculus. Both coordinate-dependent Euler–Lagrange formulations and coordinate-free Euler–Poincaré approaches are reviewed. 相似文献