全文获取类型
收费全文 | 11986篇 |
免费 | 1355篇 |
国内免费 | 2010篇 |
专业分类
化学 | 7914篇 |
晶体学 | 540篇 |
力学 | 89篇 |
综合类 | 59篇 |
数学 | 4139篇 |
物理学 | 2610篇 |
出版年
2024年 | 11篇 |
2023年 | 167篇 |
2022年 | 194篇 |
2021年 | 248篇 |
2020年 | 354篇 |
2019年 | 437篇 |
2018年 | 363篇 |
2017年 | 443篇 |
2016年 | 429篇 |
2015年 | 400篇 |
2014年 | 513篇 |
2013年 | 948篇 |
2012年 | 597篇 |
2011年 | 876篇 |
2010年 | 679篇 |
2009年 | 854篇 |
2008年 | 865篇 |
2007年 | 858篇 |
2006年 | 710篇 |
2005年 | 579篇 |
2004年 | 586篇 |
2003年 | 499篇 |
2002年 | 575篇 |
2001年 | 392篇 |
2000年 | 381篇 |
1999年 | 390篇 |
1998年 | 300篇 |
1997年 | 229篇 |
1996年 | 196篇 |
1995年 | 205篇 |
1994年 | 165篇 |
1993年 | 120篇 |
1992年 | 141篇 |
1991年 | 84篇 |
1990年 | 70篇 |
1989年 | 46篇 |
1988年 | 43篇 |
1987年 | 34篇 |
1986年 | 41篇 |
1985年 | 31篇 |
1984年 | 31篇 |
1983年 | 23篇 |
1982年 | 33篇 |
1981年 | 33篇 |
1980年 | 25篇 |
1979年 | 33篇 |
1978年 | 35篇 |
1977年 | 27篇 |
1976年 | 23篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 718 毫秒
971.
We give a characterization of the boundaries of holomorphic chains in complex projective space. This extends previous work
of the authors and complements results of Dolbeault and Henkin. 相似文献
972.
采用倒筒直流磁控溅射系统在不同溅射气体组分下(氩氧比不同)原位沉积Y1Ba2Cu2O7-δ(YBCO)薄膜.样品的XRD分析发现在Ar含量过高和过低的溅射气氛下沉积的薄膜存在极少量的BaCuO2第二相, 同时显示薄膜的c轴长度, (006), (007)对(005)峰强度比随着溅射气体中Ar含量的变化而发生改变.通过薄膜超导零电阻温度检测发现, YBCO薄膜的超导零电阻温度Tc随之发生改变.这说明在磁控溅射沉积YBCO薄膜过程中, 溅射气体中Ar气含量影响薄膜各元素的化学计量比, Ar含量过高和过低导致沉积YBCO薄膜晶体结构发生畸变, 恶化超导电性. 相似文献
973.
974.
975.
CheeWhye Chin 《Advances in Mathematics》2003,180(1):64-86
Let X be a smooth curve over a finite field of characteristic p, let ?≠p be a prime number, and let be an irreducible lisse -sheaf on X whose determinant is of finite order. By a theorem of L. Lafforgue, for each prime number ?′≠p, there exists an irreducible lisse -sheaf on X which is compatible with , in the sense that at every closed point x of X, the characteristic polynomials of Frobenius at x for and are equal. We prove an “independence of ?” assertion on the fields of definition of these irreducible ?′-adic sheaves : namely, that there exists a number field F such that for any prime number ?′≠p, the -sheaf above is defined over the completion of F at one of its ?′-adic places. 相似文献
976.
Fix a smooth very ample curve C on a K3 or abelian surface X. Let $ \mathcal{M} $ denote the
moduli space of pairs of the form (F, s), where F is a stable sheaf over X whose Hilbert polynomial
coincides with that of the direct image, by the inclusion map of C in X, of a line bundle of degree d
over C, and s is a nonzero section of F. Assume d to be sufficiently large such that F has a nonzero
section. The pullback of the Mukai symplectic form on moduli spaces of stable sheaves over X is
a holomorphic 2-form on $ \mathcal{M} $. On the other hand, $ \mathcal{M} $ has a map to a Hilbert scheme parametrizing
0-dimensional subschemes of X that sends (F, s) to the divisor, defined by s, on the curve defined
by the support of F. We prove that the above 2-form on $ \mathcal{M} $ coincides with the pullback of the
symplectic form on the Hilbert scheme. 相似文献
977.
978.
Gábor Bodnár 《Journal of Pure and Applied Algebra》2003,179(3):221-233
Given a birational projective morphism of quasi-projective varieties . We want to find the ideal sheaf over X such that the blowing up of X along corresponds to f. In this paper we approach the problem from two directions, solving two subcases. First we present a method that determines when f is the composition of blowing ups along known centers, then by another method, we compute directly from . 相似文献
979.
Javier Chavarriga 《Journal of Differential Equations》2003,194(1):116-139
We mainly study polynomial differential systems of the form dx/dt=P(x,y), dy/dt=Q(x,y), where P and Q are complex polynomials in the dependent complex variables x and y, and the independent variable t is either real or complex. We assume that the polynomials P and Q are relatively prime and that the differential system has a Darboux first integral of the form
980.
In this paper we present an inertia result for Stein equations with
an indefinite right hand side. This result is applied to establish connnections
between the inertia of invertible hermitian block Toeplitz matrices and associated
orthogonal polynomials. 相似文献