全文获取类型
收费全文 | 15685篇 |
免费 | 357篇 |
国内免费 | 412篇 |
专业分类
化学 | 1961篇 |
晶体学 | 100篇 |
力学 | 112篇 |
综合类 | 28篇 |
数学 | 11953篇 |
物理学 | 1669篇 |
无线电 | 631篇 |
出版年
2023年 | 35篇 |
2022年 | 79篇 |
2021年 | 112篇 |
2020年 | 102篇 |
2019年 | 344篇 |
2018年 | 338篇 |
2017年 | 224篇 |
2016年 | 144篇 |
2015年 | 194篇 |
2014年 | 385篇 |
2013年 | 1215篇 |
2012年 | 516篇 |
2011年 | 1038篇 |
2010年 | 878篇 |
2009年 | 961篇 |
2008年 | 1183篇 |
2007年 | 1206篇 |
2006年 | 994篇 |
2005年 | 673篇 |
2004年 | 549篇 |
2003年 | 449篇 |
2002年 | 402篇 |
2001年 | 391篇 |
2000年 | 353篇 |
1999年 | 385篇 |
1998年 | 290篇 |
1997年 | 287篇 |
1996年 | 276篇 |
1995年 | 301篇 |
1994年 | 285篇 |
1993年 | 213篇 |
1992年 | 188篇 |
1991年 | 138篇 |
1990年 | 110篇 |
1989年 | 110篇 |
1988年 | 75篇 |
1987年 | 80篇 |
1986年 | 84篇 |
1985年 | 127篇 |
1984年 | 99篇 |
1983年 | 65篇 |
1982年 | 86篇 |
1981年 | 82篇 |
1980年 | 89篇 |
1979年 | 61篇 |
1978年 | 79篇 |
1977年 | 51篇 |
1976年 | 49篇 |
1975年 | 22篇 |
1974年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Bassam Shayya 《Mathematische Zeitschrift》2009,262(1):41-55
Suppose dμ is affine surface measure on a convex radial surface Γ(x) = (x, γ(|x|)), a ≤ |x| < b, in . Under appropriate smoothness and growth conditions on γ, we prove and Fourier restriction estimates for Γ. 相似文献
992.
We study the Fano varieties of projective k-planes lying in hypersurfaces and investigate the associated motives.
The first author is partially supported by a grant from the Natural Sciences and Engineering Research Council of Canada. The
second author is partially supported by TüBİTAK-BDP funds and Bilkent University research development funds. 相似文献
993.
Igor Dolinka 《Algebra Universalis》2009,60(1):19-35
We give a sufficient condition which ensures that a semiring with an idempotent addition is inherently nonfinitely based.
This enables us to provide a number of small and natural examples of nonfinitely based semirings, including semirings of binary
relations on a finite set.
Supported by Grant No.144011 of the Ministry of Science of the Republic of Serbia. 相似文献
994.
We derive a numerical scheme to compute invariant manifolds for time-variant discrete dynamical systems, i.e., nonautonomous
difference equations. Our universally applicable method is based on a truncated Lyapunov–Perron operator and computes invariant
manifolds using a system of nonlinear algebraic equations which can be solved both locally using (nonsmooth) inexact Newton,
and globally using continuation algorithms. Compared to other algorithms, our approach is quite flexible, since it captures
time-dependent, nonsmooth, noninvertible or implicit equations and enables us to tackle the full hierarchy of strongly stable,
stable and center-stable manifolds, as well as their unstable counterparts. Our results are illustrated using a test example
and are applied to a population dynamical model and the Hénon map. Finally, we discuss a linearly implicit Euler–Bubnov–Galerkin
discretization of a reaction diffusion equation in order to approximate its inertial manifold. 相似文献
995.
This paper studies how to set the vehicle capacity for traveling Salesman Problems where some of the customer demands are
stochastic. The analyses are done for the one-commodity pickup-and-delivery TSP, as this problem also includes the setting
of the initial load. The paper first considers feasibility issues. This includes finding the smallest vehicle capacity and
some initial load such that a given tour is feasible for all scenarios. Different variants are considered as a function of
the time when information becomes available. The paper then analyzes the case where some penalties are paid for routing a
tour unable to handle customer demands. Various types of penalties are considered. The paper studies properties of the minimal
expected penalty of a given tour, which are then used to provide approaches to find near-optimal tours. Computational results
are presented. 相似文献
996.
997.
Kaushal Verma 《Mathematische Annalen》2009,344(3):645-701
Let D be a bounded domain in C
2 with a non-compact group of holomorphic automorphisms. Model domains for D are obtained under the hypotheses that at least one orbit accumulates at a boundary point near which the boundary is smooth,
real analytic and of finite type.
The author was supported by DST (India) Grant No.: SR/S4/MS-283/05 and in part by a grant from UGC under DSA-SAP, Phase IV. 相似文献
998.
Hannes Junginger-Gestrich Enrico Valdinoci 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,61(3):393-401
Using theorems of Bangert, we prove a rigidity result which shows how a question raised by Bangert for elliptic integrands
of Moser type is connected, in the case of minimal solutions without self-intersections, to a famous conjecture of De Giorgi
for phase transitions.
The work of Enrico Valdinoci was supported by MIUR Variational Methods and Nonlinear Differential Equations. Diese Zusammenarbeit
wurde bei einem sehr angenehmen Besuch von EV in Freiburg begonnen. 相似文献
999.
Brian H. Bowditch 《Mathematische Annalen》2005,332(3):667-676
Let be a singly degenerate closed surface group acting properly discontinuously on hyperbolic 3-space, H3, such that H3/ has positive injectivity radius. It is known that the limit set is a dendrite of Hausdorff dimension 2. We show that the cut-point set of the limit set has Hausdorff dimension strictly less than 2. 相似文献
1000.
Consider the following problem: how many collinear triples of points must a transversal of
have? This question is connected with venerable issues in discrete geometry. We show that the answer, for n prime, is between (n − 1)/4 and (n − 1)/2, and consider an analogous question for collinear quadruples. We conjecture that the upper bound is the truth and suggest several other interesting problems in this area.Received August 29, 2004 相似文献