全文获取类型
收费全文 | 3754篇 |
免费 | 681篇 |
国内免费 | 174篇 |
专业分类
电工技术 | 49篇 |
综合类 | 225篇 |
化学工业 | 1122篇 |
金属工艺 | 152篇 |
机械仪表 | 504篇 |
建筑科学 | 107篇 |
矿业工程 | 29篇 |
能源动力 | 92篇 |
轻工业 | 55篇 |
水利工程 | 21篇 |
石油天然气 | 36篇 |
武器工业 | 14篇 |
无线电 | 315篇 |
一般工业技术 | 639篇 |
冶金工业 | 24篇 |
原子能技术 | 29篇 |
自动化技术 | 1196篇 |
出版年
2024年 | 13篇 |
2023年 | 79篇 |
2022年 | 37篇 |
2021年 | 163篇 |
2020年 | 150篇 |
2019年 | 106篇 |
2018年 | 137篇 |
2017年 | 119篇 |
2016年 | 186篇 |
2015年 | 240篇 |
2014年 | 247篇 |
2013年 | 250篇 |
2012年 | 185篇 |
2011年 | 240篇 |
2010年 | 187篇 |
2009年 | 224篇 |
2008年 | 214篇 |
2007年 | 242篇 |
2006年 | 218篇 |
2005年 | 215篇 |
2004年 | 173篇 |
2003年 | 143篇 |
2002年 | 121篇 |
2001年 | 88篇 |
2000年 | 87篇 |
1999年 | 59篇 |
1998年 | 71篇 |
1997年 | 61篇 |
1996年 | 68篇 |
1995年 | 38篇 |
1994年 | 30篇 |
1993年 | 26篇 |
1992年 | 41篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 21篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 19篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有4609条查询结果,搜索用时 31 毫秒
21.
N. N. Man’kina A. V. Kirilina O. V. Ovechkina B. G. Lyudomirskii B. G. Rubanov Yu. G. Tikhomirov T. Sh. Zakirov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2006,40(5):307-315
Studies conducted on two power-generating units at the Kharanorskaya SAPP relative to the steam-water-oxygen passivation,
preservation, and partial cleaning of all boiler-heating surfaces, including the surfaces of the reheater, and passivation
of the surfaces of the high-pressure heaters on the steam and water sides by the steam-oxygen method, as well as partial passivation,
preservation, and cleaning of turbine blading are presented.
__________
Translated from élektricheskie Stantsii, No. 6, pp. 56–64, May, 2006. 相似文献
22.
This article presents the results from a study of yarn-to-yarn (YY) and yarn-to-metal (YM) frictions conducted on ring, rotor, air-jet, and open-end friction (OE friction) spun yarns at different relative speeds and input tensions. The results indicate that the behavior of frictions for YY is different than that of YM. In case of YY friction, OE friction yarn shows maximum friction followed by rotor, air-jet, and ring spun yarns; however, a reverse order is noticed for YM friction. The relative speed and input tension have significant influence on the frictional behavior of spun yarns. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
23.
A. Ardeshir Goshtasby Author Vitae 《Computer aided design》2003,35(5):487-494
Formulations for parametric circles and spheres in terms of rational Gaussian (RaG) curves and surfaces are introduced. With the proposed formulations, a full circle is generated by interpolating a closed RaG curve to the vertices of an equilateral triangle, and a full sphere is generated by interpolating a closed RaG surface to the vertices of an octahedron with equilateral triangular faces. Generation of circles and spheres in this manner is very intuitive and easy to remember as the weights are all 1 and the nodes are all unique and uniformly spaced. 相似文献
24.
四坐标数控加工原理及算法研究 总被引:2,自引:0,他引:2
本文对四坐标数控加工原理和算法作了详细介绍,尤其对四坐标加工的刀轴矢量算法进行了研究,提出了用垂直于回转轴的平面与刀具运动方向和前导角形成的圆锥面求交,生成刀轴矢量的方法,该方法具有立意新颖、思路清晰,性能可靠,易于在微机上实现等特点,对复杂曲面零件的加工编程,具有重要的实用价值。 相似文献
25.
FD—TD在分析FSS中的应用 总被引:3,自引:0,他引:3
本文讨论了用FD TD分析FSS的有关问题,提出了一种适合于在任意入射角情况下分析FSS的有效吸收边界条件,分别以单层、双层FSS为例进行了计算.数值结果和矢量模式法、谱域法的结果非常一致. 相似文献
26.
K.K. Padmanabhan 《Tribology International》1992,25(5)
Metallic mating surfaces in structural joints offer a good source of frictional energy dissipation resulting in a damped dynamic structural response. This paper reports the results of experiments where the energy dissipation per cycle occurring at a preloaded flat metallic annular interface subjected to cyclic tangential forces is measured. The effects of certain pertinent joint variables on this frictional energy dissipation are investigated by the application of Response Surface Methodology. A central composite rotatable design was utilized for developing empirical expressions for energy loss. The methodology presented suggests a useful technique for tribological research. 相似文献
27.
Due to their simplicity and intuitiveness, swept surfaces are widely used in many surface modelling applications. In this paper, we present a versatile swept surface technique called the boundary constrained swept surfaces. The most distinct feature is its ability to satisfy boundary constraints, including the shape and tangent conditions at the boundaries of a swept surface. This permits significantly varying surfaces to be both modelled and smoothly assembled, leading to the construction of complex objects. The representation, similar to an ordinary swept surface, is analytical in nature and thus it is light in storage cost and numerically very stable to compute. We also introduce a number of useful shape manipulation tools, such as sculpting forces, to deform a surface both locally and globally. In addition to being a complementary method to the mainstream surface modelling and deformation techniques, we have found it very effective in automatically rebuilding existing complex models. Model reconstruction is arguably one of the most laborious and expensive tasks in modelling complex animated characters. We demonstrate how our technique can be used to automate this process. 相似文献
28.
用偏微分方程构造过渡面 总被引:9,自引:2,他引:7
用偏微分方程的构造曲面是一种新兴的方法,本文借若干算例说明如何用偏微分方程构造两已知曲面之间的过渡面。论文着重讨论用四阶方程构造一阶连续的过渡面。 相似文献
29.
在高地震烈度区的岩石高边坡抗震安全评价需要大规模数值计算,而现有商业软件无法有效解决这类复杂的工程问题,因此,本文开发了解决岩石高边坡接触稳定性问题的对等架构并行计算程序,并应用于泰山公司抽水蓄能电站上水库左岸边坡的静力和动力稳定性评价。在数值建模过程中,将岩石边坡滑块体、地质结构面、库水作用以及近场地基作为岩石高边坡动力接触系统。在稳定性安全评价中结合了有限元法、极限平衡法和接触算法,考虑影响高边坡稳定性的多种复杂因素,通过计算特定滑动面的安全系数或安全系数时程,基于现行水电工程水工建筑物抗震设计规范,完成了岩石高边坡稳定性评价,回避了求解复杂岩体材料非线性的问题。计算结果显示,所开发的程序具有较高的并行计算效率,对解决复杂岩石高边坡稳定问题具有显著的优势。 相似文献
30.