全文获取类型
收费全文 | 1622篇 |
免费 | 18篇 |
国内免费 | 62篇 |
专业分类
化学 | 694篇 |
晶体学 | 3篇 |
力学 | 431篇 |
综合类 | 4篇 |
数学 | 118篇 |
物理学 | 452篇 |
出版年
2024年 | 5篇 |
2023年 | 141篇 |
2022年 | 12篇 |
2021年 | 17篇 |
2020年 | 26篇 |
2019年 | 62篇 |
2018年 | 29篇 |
2017年 | 34篇 |
2016年 | 29篇 |
2015年 | 34篇 |
2014年 | 42篇 |
2013年 | 99篇 |
2012年 | 39篇 |
2011年 | 61篇 |
2010年 | 56篇 |
2009年 | 90篇 |
2008年 | 97篇 |
2007年 | 92篇 |
2006年 | 111篇 |
2005年 | 79篇 |
2004年 | 67篇 |
2003年 | 66篇 |
2002年 | 67篇 |
2001年 | 53篇 |
2000年 | 61篇 |
1999年 | 28篇 |
1998年 | 18篇 |
1997年 | 28篇 |
1996年 | 18篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
排序方式: 共有1702条查询结果,搜索用时 31 毫秒
101.
In this paper, we study the equilibrium properties of polymer chains end-tethered to a fluid membrane. The loss of conformational
entropy of the polymer results in an inhomogeneous pressure field that we calculate for Gaussian chains. We estimate the effects
of excluded volume through a relation between pressure and concentration. Under the polymer pressure, a soft surface will
deform. We calculate the deformation profile for a fluid membrane and show that close to the grafting point, this profile
assumes a cone-like shape, independently of the boundary conditions. Interactions between different polymers are also mediated
by the membrane deformation. This pair-additive potential is attractive for chains grafted on the same side of the membrane
and repulsive otherwise.
Received 20 April 2000 相似文献
102.
首先对微晶粒尺寸增长速率的表征进行总结.从微晶核和粒—高分子链组网络结构特点(高分子链组是微晶核和微晶粒同连接链段的复合体)同增长速率间的三个相关性的特征: ①晶核和晶粒加大同连接链段缩短的并存性; ②微晶核和粒表面上连接链段的缩短机制存有简并性; ③微晶粒内和粒表面上stem的反顺式构象共存性出发.建议了一种评估和计算微晶粒尺寸增长速率的新方法和原则,基于该种计算方法和原则用统计力学和动力学相结合法推导出了高分子熔体内几种不同结晶生长机制(近邻折叠、近邻伸直分凝和近邻折叠同近邻伸直分凝并存等生长方式)下微晶粒—高分子链组中微晶粒数增长速率和微晶粒尺寸增长速率动力学方程. 相似文献
103.
104.
F. F. Gong F. X. Gong F. Y. Gong 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,49(3):267-268
Open dynamic behaviour of financial markets with internal
interactions between agents and with external “fields” from other systems
are investigated using the approach of Grossman and Stiglitz for inefficient
markets, and Keynes for interference of the market using physics of finance
(referred to hereafter as phynance). The simulation results indicate that
the NYSE data analyzed in Plerou, V. et al., Nature 421, 130 (2003) can be fitted
by an equation of order parameter Φ and local deviation R of type:
-(R+0.03) Φ+ 0.6 Φ3 + 0.02 = 0, which is shown to be in
remarkable agreement with Plerou's data. 相似文献
105.
生态环境脆弱区工程地质研究是工程地质学科必须面对的一个重要领域。作者指出,工程地质学应当夯实学科基础,吸取相关学科理论,重塑工程地质理论与实践,出精品工程,重视人才培养。 相似文献
106.
根据在浙江苍岭隧道施工中发生的岩爆,通过现场地质观测资料,具体地分析了其形成的规模、位置、诱发因素以及地质条件,从地质工程的角度,对岩爆发生地段隧道的岩石组成、地质构造、地应力特征以及地下水情况进行了探讨,发现在苍岭隧道施工中发生岩爆的岩石具有岩体结构面发育适中、弹性模量大、P波波速高、地质构造简单、现代水平构造应力强且主压应力轴σ1大角度相交于隧道中轴线和地下水不发育的特征,并在此基础上,提出了掌子面喷水、布设释放地应力锚杆、减少隧道壁聚能结构等有效的岩爆防治措施。 相似文献
107.
A recently developed coupled third-order zigzag theory for the statics of piezoelectric hybrid cross-ply plates is extended
to dynamics. The theory combines a third-order zigzag approximation for the in-plane displacements and a sub-layerwise linear
approximation for the electric potential, considering all components of the electric field. The nonuniform variation of the
transverse displacement due to the piezoelectric field is accounted for. The conditions for the absence of shear traction
at the top and bottom surfaces and continuity of transverse shear stresses in the presence of electromechanical loading are
satisfied exactly, thereby reducing the number of displacement variables to five, which is the same as in a first- or third-order
equivalent single-layer theory. The governing equations of motion are derived from the extended Hamilton's principle. The
theory is assessed by comparing the Navier solutions for the free and forced harmonic vibration response of simply supported
plates with the exact three-dimensional piezoelasticity solutions. Comparisons for hybrid test, composite and sandwich plates
establish that the present theory is quite accurate for the dynamic response of moderately thick plates. 相似文献
108.
In the present work, the evolution of the inelastic centre deflections of shock wave-loaded circular metal plates due to repeated loadings is studied experimentally and numerically. These displacements are compared to those of quasi-statically deformed plates loaded by a pressure equal to the peak pressure of the impulsive loading. Thereby three types of permanent centre deflections are observed: (1) The quasi-statically obtained deflection is exceeded by the middle point displacement of a dynamically loaded structure already after the first impulse and tends towards a limit state after repeated shock wave-loadings. (2) The centre deflection of the impulsively loaded plate exceeds also the quasi-statically caused deflection and does not increase after repeated impulsive loadings any more. (3) The permanent middle point displacement of a dynamically loaded plate is smaller than the deflection of a quasi-statically loaded one and tends towards the middle point displacement of the quasi-static counterpart after repeated shock wave loadings. This phenomenon is known in the literature as ‘Pseudo-shakedown’.
In Part 1 of this study the experimental observation is described, followed by a theoretical study in Part 2. 相似文献
109.
This study is in keeping with the general pattern of dynamical simulations of a set of rigid three-dimensional bodies submitted to unilateral contact constraints with dry friction. An exact formulation (respecting the contact and friction laws) of the problem of predicting the system accelerations and the contact status, in further evolution is proposed. A numerical treatment of this kind of nonlinear problem is presented. This approach is applied to a simple multi-contact example, and yields results in agreement with those of analytical and numerical type, known for this example. To cite this article: C. Le Saux et al., C. R. Mecanique 331 (2003). 相似文献
110.
红粘土的微结构及其概化模型 总被引:3,自引:0,他引:3
本文论述红粘土的物质组成和微结构特征,在此基础上提出了红粘土微结构的概化模型,并根据这种模型对红粘土的工程特性进行了探讨。 相似文献