全文获取类型
收费全文 | 1419篇 |
免费 | 54篇 |
国内免费 | 32篇 |
专业分类
化学 | 521篇 |
晶体学 | 27篇 |
力学 | 24篇 |
综合类 | 7篇 |
数学 | 376篇 |
物理学 | 550篇 |
出版年
2021年 | 5篇 |
2020年 | 14篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 34篇 |
2012年 | 26篇 |
2011年 | 13篇 |
2010年 | 24篇 |
2009年 | 84篇 |
2008年 | 107篇 |
2007年 | 92篇 |
2006年 | 76篇 |
2005年 | 64篇 |
2004年 | 82篇 |
2003年 | 100篇 |
2002年 | 65篇 |
2001年 | 73篇 |
2000年 | 50篇 |
1999年 | 35篇 |
1998年 | 36篇 |
1997年 | 22篇 |
1996年 | 40篇 |
1995年 | 35篇 |
1994年 | 50篇 |
1993年 | 31篇 |
1992年 | 41篇 |
1991年 | 31篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 11篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 18篇 |
1983年 | 4篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 18篇 |
1979年 | 23篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1972年 | 3篇 |
排序方式: 共有1505条查询结果,搜索用时 15 毫秒
1.
2.
We introduce the concept of cumulative Parisian ruin, which is based on the time spent in the red by the underlying surplus process. Our main result is an explicit representation for the distribution of the occupation time, over a finite-time horizon, for a compound Poisson process with drift and exponential claims. The Brownian ruin model is also studied in details. Finally, we analyse for a general framework the relationships between cumulative Parisian ruin and classical ruin, as well as with Parisian ruin based on exponential implementation delays. 相似文献
3.
Yutaka Yoshii 《代数通讯》2017,45(1):1-8
Let G be a connected, semisimple, and simply connected algebraic group defined and split over the finite field of order p, and let G(q) be the corresponding finite Chevalley or twisted group, where q = pr. Recently, Anwar determines the direct sum decomposition of the tensor product of the rth Steinberg module and a simple G-module with a (p,r)-minuscule highest weight λ. In this paper, we determine that of the tensor product regarded as a module for G(q) under some weak assumptions for λ. 相似文献
4.
5.
A few additional data from our previous experiments were plotted to emphasize the shear-thickening behavior of deoxy sickle erythrocyte (SS) suspension. A constitutive equation (named as FX equation) was developed and applied to a cylindrical pipe flow of a shear-thickening fluid. A blunt velocity profile and its volume flow rate were calculated. The flow was non-viscous (potential) in the central part of the pipe (i.e. the central core or the central plug-flow), and became more and more viscous towards the wall of the pipe after a specific radial distance, which was determined by a critical shear rate of (named as Fungs shear rate). Furthermore, combining the FX equation with the original Cassons equation, the author obtained a modified Cassons equation by introducing .The English text was polished by Yunming Chen. 相似文献
6.
A. G. Kolpakov 《Journal of Applied Mechanics and Technical Physics》2003,44(4):584-595
A method for solving the problem of design of an intellectual structure formulated for the pair optimal position of actuators, optimal control of actuators is developed. In the method proposed, physical and logical objects are treated as equivalent. 相似文献
7.
The paper deals with the simulation program Off Road Systems Interactive Simulation (ORSIS) which is the w,orldwide leading simulation tool for off road driving of wheeled vehicles. Even though the present state of development allows a very realistic simulation of the man–vehicle–terrain system, there is continuous further improvement in the computer program’s detail. Some of the recent innovations integrated into the program are presented in this paper. These examples were chosen in a way that the scope of the further developments can be demonstrated. They represent three main directions of the work carried out: the refining of the tire–soil-model, the integration of new technologies and subsystems into the vehicle model and the improvement of the man–machine–interface especially in driving simulators.The first part of the paper describes a further development of the tire–soil-model. A significant improvement has been achieved to include the influence of slippery surfaces on traction in combination with the tire tread pattern. Results from finite element method (FEM) as well as real measurements were used to build up an approach, which qualitatively allows the influence of the positive–negative portion of the tire tread and the lug height of the tire tread on traction to be considered. The basic idea is very simple and straightforward. Moreover the calculation costs are very low, so the enhancement does not affect real time operation.In the second part a physical model for the central tire inflation system (CTIS) is presented. With this model it is possible to simulate the complete pneumatic system of a CTIS, including the air compressor with an accumulator, the pressure line and the wheel valves. The components are modelled by their physical parameters, so an adaptation to different existing tire-pressure-control-systems (TPC) can be made. The paper presents a short review of the modelling and a first validation using real measurements. Furthermore the influence of each parameter, e.g. the discharge flow of the compressor on the inflation time, is presented.The third part of the paper describes a further development of the visualization system. The ORSIS OpenGL graphic engine was separated from the main ORSIS simulation and can be run on different PCs controlled via a network. It is therefore possible to build up very cheap multi-channel visualization systems using consumer PCs running under LinuX. The fact that ORSIS itself is running on a normal PC allows the assembly of comparatively cheap driving simulators of a high end simulation quality. 相似文献
8.
9.
We study scalar diffusion, both from Eulerian and Lagrangian perspectives, advected by two dimensional flows. Emphasis is devoted to the problem of scalar diffusion under a synthetic turbulent flow. We present numerical and analytical results for the turbulent diffusion coefficient either from the influence of the turbulent synthetic field and a periodic array of eddies. Preliminary results concerning Lagrangian dispersion are also reported. 相似文献
10.
华云 《数学的实践与认识》2012,42(13):218-221
给出了二阶导数属于Lp空间时Fejér和Hermite-Hadamard型不等式的推广,得到两个新结果. 相似文献