全文获取类型
收费全文 | 19891篇 |
免费 | 1594篇 |
国内免费 | 1141篇 |
专业分类
化学 | 1858篇 |
晶体学 | 21篇 |
力学 | 2508篇 |
综合类 | 173篇 |
数学 | 14478篇 |
物理学 | 3588篇 |
出版年
2024年 | 36篇 |
2023年 | 193篇 |
2022年 | 188篇 |
2021年 | 321篇 |
2020年 | 531篇 |
2019年 | 522篇 |
2018年 | 529篇 |
2017年 | 522篇 |
2016年 | 539篇 |
2015年 | 442篇 |
2014年 | 827篇 |
2013年 | 1998篇 |
2012年 | 836篇 |
2011年 | 1130篇 |
2010年 | 983篇 |
2009年 | 1282篇 |
2008年 | 1243篇 |
2007年 | 1219篇 |
2006年 | 1088篇 |
2005年 | 895篇 |
2004年 | 777篇 |
2003年 | 782篇 |
2002年 | 732篇 |
2001年 | 609篇 |
2000年 | 602篇 |
1999年 | 535篇 |
1998年 | 447篇 |
1997年 | 415篇 |
1996年 | 327篇 |
1995年 | 223篇 |
1994年 | 245篇 |
1993年 | 189篇 |
1992年 | 156篇 |
1991年 | 124篇 |
1990年 | 112篇 |
1989年 | 89篇 |
1988年 | 73篇 |
1987年 | 73篇 |
1986年 | 63篇 |
1985年 | 92篇 |
1984年 | 118篇 |
1983年 | 57篇 |
1982年 | 82篇 |
1981年 | 70篇 |
1980年 | 66篇 |
1979年 | 61篇 |
1978年 | 59篇 |
1977年 | 38篇 |
1976年 | 34篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
A. B. Mitkevich 《Mechanics of Composite Materials》2005,41(6):497-504
Errors in the programs of winding pressure vessels can lead to an asymmetric reinforcement structure, which affects the equilibrium
shape of their domes and the tension in the left and right families of filaments. In this paper, equations determining the
equilibrium shape of the domes, the tension in filaments, and the shear stresses between layers are obtained. Examples with
winding trajectories in the form of geodesics and constant-deviation lines are considered. It is found that, for pressure
vessels, in the absence of external torque, the tension levels in filaments of the left and right families differ considerably.
It is also revealed that, for actual friction coefficients in winding, the shear stresses taken up by the binder are insignificant.
__________
Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 6, pp. 743–752, November–December, 2005. 相似文献
52.
We treat here of the question of absorbing boundary conditionsfor nonlinear diffusion equations. We use the conditions designedfor the linear equation, we prove them to be well posed forthe nonlinear problem, and through numerical experiments thatthey are well suited for reactiondiffusion equations. 相似文献
53.
V. I. Sakharov 《Fluid Dynamics》2007,42(6):1007-1016
The results of numerical simulation are presented for thermally and chemically nonequilibrium air plasma flows in a plasmatron discharge channel and underexpanded dissociated and partially ionized air jets flowing past a cylindrical model with a blunt leading edge and cooled copper surface under the experimental conditions realized in a VGU-4 100 kW induction plasmatron (Institute for Problems in Mechanics of the Russian Academy of Sciences) (see, for example, [1, 2]). The nonequilibrium excitation of the vibrational degrees of freedom of the molecules in the modal approximation and the difference between the electron and translational heavy-particle temperatures are taken into account in the calculations. The calculated data on the heat transfer and pressure at the stagnation point are compared with the results obtained within the framework of the thermally equilibrium model. Comparison with the experimental data obtained in the Institute for Problem in Mechanics of the Russian Academy of Sciences (Laboratory for interaction between plasma and radiation and materials) and kindly provided for comparison purposes gives satisfactory agreement. 相似文献
54.
55.
Frank Jochmann 《Journal of Differential Equations》2004,203(2):232-254
In this paper, Maxwell's equations involving generally nonlinear polarization and field-dependent currents are studied. The main objective is the asymptotic behavior of the solution for t→∞ if no damping term occurs in the equation governing the polarization field. 相似文献
56.
Svitlana P. Rogovchenko 《Journal of Mathematical Analysis and Applications》2003,279(1):121-134
In this paper, we are concerned with a class of nonlinear second-order differential equations with a nonlinear damping term. Passage to more general class of equations allows us to remove a restrictive condition usually imposed on the nonlinearity, and, as a consequence, our results apply to wider classes of nonlinear differential equations. Two illustrative examples are considered. 相似文献
57.
管理中的Nash平衡与Braess悖论现象 总被引:3,自引:0,他引:3
本给出了交通规划、经济贸易以及其它管理中的一些Nash平衡和Braess悖论实例,分析了Nash平衡和Braess悖论现象及其本质特征,指出它们在管理工作中具有普遗性和潜在应用性。 相似文献
58.
MC模式下顾客需求与厂商供应的纳什均衡 总被引:3,自引:0,他引:3
在大规模定制(MC,Mass Customization)模式下,基于市场需求的复杂化,厂商对个性化的顾客需求很难做出及时准确的反应,而且由于其自身生产能力的限制,不可能对所有的个性化用户进行一一地满足,只可能对已经存在的个性化需求,根据自身的生产能力和规模,以利润最大化及顾客对产品的满意度为目标,对个性化需求进行较准确地预测,从而正确指导生产。本通过博弈论的方法,提出了一个基于顾客对产品的满意度及企业的利润的一个非合作博弈模型,并给出求解纳什均衡的方法。 相似文献
59.
本文提供了预条件不精确牛顿型方法结合非单调技术解光滑的非线性方程组.在合理的条件下证明了算法的整体收敛性.进一步,基于预条件收敛的性质,获得了算法的局部收敛速率,并指出如何选择势序列保证预条件不精确牛顿型的算法局部超线性收敛速率. 相似文献
60.
In this Letter we consider the Abelian Chern–Simons vortices on a bounded simply connected domain. We establish the existence of solutions for the self-duality equations. We prove the uniqueness of solutions when all the vortex points are equal and the domain is star-shaped. We also show the radial symmetry of solutions on balls centered at the vortex point. 相似文献