全文获取类型
收费全文 | 66762篇 |
免费 | 8126篇 |
国内免费 | 5244篇 |
专业分类
电工技术 | 5652篇 |
技术理论 | 6篇 |
综合类 | 6955篇 |
化学工业 | 10153篇 |
金属工艺 | 2799篇 |
机械仪表 | 4901篇 |
建筑科学 | 4037篇 |
矿业工程 | 1989篇 |
能源动力 | 5404篇 |
轻工业 | 2174篇 |
水利工程 | 5583篇 |
石油天然气 | 5239篇 |
武器工业 | 725篇 |
无线电 | 3597篇 |
一般工业技术 | 5461篇 |
冶金工业 | 3294篇 |
原子能技术 | 1518篇 |
自动化技术 | 10645篇 |
出版年
2024年 | 335篇 |
2023年 | 1014篇 |
2022年 | 1833篇 |
2021年 | 2125篇 |
2020年 | 2280篇 |
2019年 | 1954篇 |
2018年 | 1875篇 |
2017年 | 2349篇 |
2016年 | 2577篇 |
2015年 | 2717篇 |
2014年 | 3747篇 |
2013年 | 4351篇 |
2012年 | 4399篇 |
2011年 | 5189篇 |
2010年 | 3715篇 |
2009年 | 4016篇 |
2008年 | 3886篇 |
2007年 | 4558篇 |
2006年 | 4196篇 |
2005年 | 3690篇 |
2004年 | 3117篇 |
2003年 | 2710篇 |
2002年 | 2191篇 |
2001年 | 1793篇 |
2000年 | 1548篇 |
1999年 | 1319篇 |
1998年 | 1100篇 |
1997年 | 908篇 |
1996年 | 854篇 |
1995年 | 767篇 |
1994年 | 668篇 |
1993年 | 495篇 |
1992年 | 414篇 |
1991年 | 266篇 |
1990年 | 264篇 |
1989年 | 211篇 |
1988年 | 140篇 |
1987年 | 100篇 |
1986年 | 75篇 |
1985年 | 62篇 |
1984年 | 67篇 |
1983年 | 51篇 |
1982年 | 35篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 25篇 |
1978年 | 12篇 |
1977年 | 14篇 |
1959年 | 23篇 |
1951年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
A framework is presented for examining the effectiveness of limiting and modelling arguments used in the analysis of fluid
flows. It consists of examining the consequences of the arguments on the flow problem as a whole and breaking down the limiting/modelling
process into a sequence of steps and associated sequence of flow problems, termed here as ‘lidels’. The notion of validity
of lidels is given. Several examples are given to explain the present approach.
Invited general lecture at 3rd ACFM, Tokyo, September 1986 相似文献
83.
Li Wei College of water conservancy Hydropower Engineering Wuhan Univerity Wuhan ChinaChen Wen-xue Xie Sheng-zong China Institute of Water Resources Hydropower Research Beijing China 《水动力学研究与进展(B辑)》2002,14(4)
1 . INTRODUCTIONTheturbulentstructuresinnon circularductsandopenchannelsarecharacterizedbylongitudi nalvortices .Thesevorticesareth 相似文献
84.
85.
86.
87.
Asynchronous design techniques have a number of compelling features that make them suited for complex system on chip designs. However, it is necessary to develop practical and efficient design techniques to overcome the present shortage of commercial design tools. This paper describes the development of CADRE (Configurable Asynchronous DSP for Reduced Energy), a 750K transistor, high performance, low-power digital signal processor IP block intended for digital mobile phone chipsets. A short time period was available for the project, and so a methodology was developed that allowed high-level simulation of the design at the earliest possible stage within the conventional schematic entry environment and simulation tools used for later circuit-level performance and power consumption assessment. Initial modeling was based on C behavioral models of the various data and control components, with the many asynchronous control circuits required automatically generated from their specifications. This has enabled design options to be explored and unusual features of the design, such as the Register Bank which is designed to exploit data access patterns, are presented along with the power and performance results of the processor as a whole. 相似文献
88.
A variant of the boundary element method, called the boundary contour method (BCM), offers a further reduction in dimensionality.
Consequently, boundary contour analysis of two-dimensional (2-D) problems does not require any numerical integration at all.
While the method has enjoyed many successful applications in linear elasticity, the above advantage has not been exploited
for Stokes flow problems and incompressible media. In order to extend the BCM to these materials, this paper presents a development
of the method based on the equations of Stokes flow and its 2-D kernel tensors. Potential functions are derived for quadratic
boundary elements. Numerical solutions for some well-known examples are compared with the analytical ones to validate the
development.
Received 28 August 2001 / Accepted 15 January 2002 相似文献
89.
90.
正交曲线坐标下三维代数应力通量模型 总被引:7,自引:1,他引:6
针对弯曲及不规则明渠的水动力及物质输运特性,本文建立了曲线坐标系下的三维代数应力通量数学模型,对平面上弯曲及不规则复杂边界情形,采用Poisson方程进行正交曲线坐标变换,各向异性的湍流代数应力通量模型被引用于本文的模拟计算中,以体现复杂边界条件引起的水动力及物质输运特性的变化。通过180度强弯曲明渠水槽及贵溪电厂不规则边界河段物理模型试验两个实例计算表明,实测值与计算吻合良好,效果令人满意。 相似文献