全文获取类型
收费全文 | 19674篇 |
免费 | 2516篇 |
国内免费 | 867篇 |
专业分类
化学 | 2430篇 |
晶体学 | 172篇 |
力学 | 3340篇 |
综合类 | 300篇 |
数学 | 11438篇 |
物理学 | 5377篇 |
出版年
2024年 | 37篇 |
2023年 | 184篇 |
2022年 | 418篇 |
2021年 | 501篇 |
2020年 | 455篇 |
2019年 | 438篇 |
2018年 | 437篇 |
2017年 | 626篇 |
2016年 | 632篇 |
2015年 | 452篇 |
2014年 | 863篇 |
2013年 | 1242篇 |
2012年 | 1108篇 |
2011年 | 957篇 |
2010年 | 904篇 |
2009年 | 1069篇 |
2008年 | 1116篇 |
2007年 | 1268篇 |
2006年 | 1090篇 |
2005年 | 1047篇 |
2004年 | 866篇 |
2003年 | 890篇 |
2002年 | 790篇 |
2001年 | 699篇 |
2000年 | 674篇 |
1999年 | 579篇 |
1998年 | 509篇 |
1997年 | 479篇 |
1996年 | 326篇 |
1995年 | 326篇 |
1994年 | 258篇 |
1993年 | 252篇 |
1992年 | 201篇 |
1991年 | 174篇 |
1990年 | 149篇 |
1989年 | 98篇 |
1988年 | 99篇 |
1987年 | 86篇 |
1986年 | 76篇 |
1985年 | 114篇 |
1984年 | 100篇 |
1983年 | 39篇 |
1982年 | 55篇 |
1981年 | 64篇 |
1980年 | 40篇 |
1979年 | 64篇 |
1978年 | 59篇 |
1977年 | 59篇 |
1976年 | 37篇 |
1974年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2021,38(5):1337-1371
In this paper we consider minimizers of the functional where is a bounded open set and where are the first k eigenvalues on Ω of an operator in divergence form with Dirichlet boundary condition and with Hölder continuous coefficients. We prove that the optimal sets have finite perimeter and that their free boundary is composed of a regular part, which is locally the graph of a -regular function, and a singular part, which is empty if , discrete if and of Hausdorff dimension at most if , for some . 相似文献
3.
《Mendeleev Communications》2022,32(4):507-509
We report on the synthesis of new Ru(bpy)2(phen) catalyst for the oscillatory Belousov–Zhabotinsky chemical reaction and on the preparation of novel Ru(bpy)2(phen)-based self-oscillating gels. The synthesized gels exhibit high-amplitude autonomous mechanical oscillations when the Belousov–Zhabotinsky reaction proceeds inside these gels 相似文献
4.
In this article, we construct and analyze a residual-based a posteriori error estimator for a quadratic finite volume method (FVM) for solving nonlinear elliptic partial differential equations with homogeneous Dirichlet boundary conditions. We shall prove that the a posteriori error estimator yields the global upper and local lower bounds for the norm error of the FVM. So that the a posteriori error estimator is equivalent to the true error in a certain sense. Numerical experiments are performed to illustrate the theoretical results. 相似文献
5.
6.
Sze-Jack Tan Chee-Keong Lee Chee-Yuen Gan Olusegun Abayomi Olalere 《Molecules (Basel, Switzerland)》2021,26(7)
In this study, the combination of parameters required for optimal extraction of anti-oxidative components from the Chinese lotus (CLR) and Malaysian lotus (MLR) roots were carefully investigated. Box–Behnken design was employed to optimize the pH (X1: 2–3), extraction time (X2: 0.5–1.5 h) and solvent-to-sample ratio (X3: 20–40 mL/g) to obtain a high flavonoid yield with high % DPPHsc free radical scavenging and Ferric-reducing power assay (FRAP). The analysis of variance clearly showed the significant contribution of quadratic model for all responses. The optimal conditions for both Chinese lotus (CLR) and Malaysian lotus (MLR) roots were obtained as: CLR: X1 = 2.5; X2 = 0.5 h; X3 = 40 mL/g; MLR: X1 = 2.4; X2 = 0.5 h; X3 = 40 mL/g. These optimum conditions gave (a) Total flavonoid content (TFC) of 0.599 mg PCE/g sample and 0.549 mg PCE/g sample, respectively; (b) % DPPHsc of 48.36% and 29.11%, respectively; (c) FRAP value of 2.07 mM FeSO4 and 1.89 mM FeSO4, respectively. A close agreement between predicted and experimental values was found. The result obtained succinctly revealed that the Chinese lotus exhibited higher antioxidant and total flavonoid content when compared with the Malaysia lotus root at optimum extraction condition. 相似文献
7.
8.
Bobby Wilson 《偏微分方程通讯》2015,40(8):1521-1542
This article explores the questions of long time orbital stability in high order Sobolev norms of plane wave solutions to the NLSE in the defocusing case. 相似文献
9.
Recent Progress in the $L_p$ Theory for Elliptic and Parabolic Equations with Discontinuous Coefficients
下载免费PDF全文
![点击此处可从《分析论及其应用》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hongjie Dong 《分析论及其应用》2020,36(2):161-199
In this paper, we review some results over the last 10-15 years on elliptic and parabolic equations with discontinuous coefficients. We begin with an approach given by N. V. Krylov to parabolic equations in the whole space with $\rm{VMO}_x$ coefficients. We then discuss some subsequent development including elliptic and parabolic equations with coefficients which are allowed to be merely measurable in one or two space directions, weighted $L_p$estimates with Muckenhoupt ($A_p$) weights, non-local elliptic and parabolic equations, as well as fully nonlinear elliptic and parabolic equations. 相似文献
10.
非线性互补问题的一种全局收敛的显式光滑Newton方法 总被引:2,自引:0,他引:2
本针对Po函数非线性互补问题,给出了一种显式光滑Newton方法,该方法将光滑参数μ进行显式迭代而不依赖于Newton方向的搜索过程,并在适当的假设条件下,证明了算法的全局收敛性。 相似文献