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1.
传统的破片式防空反导战斗部爆炸后产生的破片杀伤元数量虽多,却不能有效击毁来袭的不敏感弹药,存在威力不足问题,因而限制了其发展。周向多线性爆炸成型弹丸(multiple linear explosively-formed projectile, MLEFP)战斗部爆炸后在周向产生多个高速、大质量、大长径比的对折型线性爆炸成型弹丸(linear explosively-formed projectile, LEFP),具备击穿、击爆厚壁壳体不敏感弹药的能力,因此在中近程防空反导作战中具备广阔的应用前景。从线性毁伤元的发展和对折型LEFP的成型技术出发,重点分析了炸药装药、药型罩等关键部件影响线性毁伤元成型的研究成果,对比了3种毁伤元初速工程计算模型的理论依据、优缺点等,概括了近年来对折型LEFP侵彻试验结果,最后总结了周向MLEFP战斗部及其毁伤元未来的发展方向。 相似文献
2.
Zhong Weizhou Zhang Zexiong Chen Xiaowei Wei Qiang Chen Gang Huang Xicheng 《Acta Mechanica Sinica》2021,37(7):1136-1151
Acta Mechanica Sinica - Multi-scale finite element method is adopted to simulate wood compression behavior under axial and transverse loading. Representative volume elements (RVE) of wood... 相似文献
3.
以二级轻气炮作为加载手段,针对以PTFE/Al活性材料为防护屏的Whipple防护结构,开展不同弹丸尺寸、不同碰撞速度的超高速撞击实验。利用激光阴影照相设备,获得并分析了碎片云特性;通过回收的防护结构靶板,研究了活性材料防护结构超高速撞击条件下的后板损伤特性;通过与经典Christiansen撞击极限方程对比,获得活性材料Whipple结构防护性能,并拟合得到新型防护结构的撞击极限曲线。结果表明,相较于同面密度铝合金材料,活性材料超高速撞击条件下的冲击起爆反应使得碎片云中具有侵彻能力的碎片大幅减少,从而显著提升航天器的防护能力,撞击速度为2.31 km/s时最大可提升45%。 相似文献
4.
《力学快报》2021,11(6):100309
The present study provides a three-dimensional volume-of-fluid method based on the adaptive mesh refinement technique. The projection method on the adaptive mesh is introduced for solving the incompressible Navier-Stokes equations. The octree structure mesh is employed to solve the flow velocities and the pressure. The developed solver is applied to simulate the deformation of the cubic droplet driven by the surface tension without the effect of the gravity. The numerical results well predict the shape evolution of the droplet. 相似文献
5.
Denote a semisimple Banach algebra with an identity e by A.This paper studies the Fredholm,Weyl and Browder spectral theories in a semisimple Banach algebra,and meanwhile considers the properties of the Fredholm element,the Weyl element and the Browder element.Further,for a∈A,we give the Weyl's theorem and the Browder's theorem for a,and characterize necessary and sufficient conditions that both a and f(a) satisfy the Weyl's theorem or the Browder's theorem,where f is a complex-valued function analytic on a neighborhood of σ(a).In addition,the perturbations of the Weyl's theorem and the Browder's theorem are investigated. 相似文献
6.
In this paper,we prove that any κ-noncollapsed gradient steady Ricci soliton with nonnegative curvature operator and horizontally κ-pinched Ricci curvature must be rotationally symmetric.As an application,we show that any κ-noncollapsed gradient steady Ricci soliton(Mn,g,f) with nonnegative curvature operator must be rotationally symmetric if it admits a unique equilibrium point and its scalar curvature R(x) satisfies lim_(ρ(x)→∞) R(x)f(x)=C_0 sup_(x∈M) R(x) with C_0n-2/2. 相似文献
7.
This paper visualizes and analyzes an effect of a wheel camber angle for the slope traversability in sandy terrain. An in-wheel camera developed in this work captures the wheel-soil contact phenomenon generated beneath the wheel through a transparent section of the wheel surface. The images taken by the camera are then analyzed using the particle image velocimetry. The soil flows with various wheel camber angles are analyzed with regard to the soil failure observed on the slope surface. The analysis reveals that the slope failure and soil accumulation in front of the wheel significantly affect the wheel forces and distributions of the wheel sinkage in the wheel width direction. Further, the side force of the wheel in traversing a slope decreases as the slip ratio increases because the shear stress in the slope downward direction decreases owing to the slope failure. 相似文献
8.
9.
本文提出了一种应用于光纤延时系统中实现光纤延时精密测量的新方法,用以提高光纤延时测量的精度和准确性.该方法以1064 nm激光调制信号作为光源,通过测量回波信号的幅值和相位信息得到被测通道的频率响应,采用快速傅里叶逆变换得到被测目标的延时信息,实现光纤延时测量.本文通过理论分析和延时测量实验对频域反射法与传统的时域测量方法进行对比,使用频域反射法在调制频率范围10—200 MHz,采样频率间隔0.5 MHz的实验条件下,实现了3.3 ps延时测量分辨率,并证明了该方法具有比时域方法更高的测量精度,测量结果的准确性更好. 相似文献
10.
The classical critical Trudinger-Moser inequality in R~2 under the constraint ∫_(R_2)(|▽u|~2+|u|~2)dx≤1 was established through the technique of blow-up analysis or the rearrangement-free argument:for any τ 0,it holds that ■ and 4π is sharp.However,if we consider the less restrictive constraint ∫_(R_2)(|▽u|~2+|u|~2)dx≤1,where V(x) is nonnegative and vanishes on an open set in R~2,it is unknown whether the sharp constant of the Trudinger-Moser inequality is still 4π.The loss of a positive lower bound of the potential V(x) makes this problem become fairly nontrivial.The main purpose of this paper is twofold.We will first establish the Trudinger-Moser inequality ■ when V is nonnegative and vanishes on an open set in R~2.As an application,we also prove the existence of ground state solutions to the following Sciridinger equations with critical exponeitial growth:-Δu+V(x)u=f u) in R~2,(0.1)where V(x)≥0 and vanishes on an open set of R~2 and f has critical exponential growth.Having a positive constant lower bound for the potential V(x)(e.g.,the Rabinowitz type potential) has been the standard assumption when one deals with the existence of solutions to the above Schr?dinger equations when the nonlinear term has the exponential growth.Our existence result seems to be the first one without this standard assumption. 相似文献