全文获取类型
收费全文 | 10325篇 |
免费 | 925篇 |
国内免费 | 1292篇 |
专业分类
化学 | 5839篇 |
晶体学 | 128篇 |
力学 | 488篇 |
综合类 | 191篇 |
数学 | 4365篇 |
物理学 | 1531篇 |
出版年
2024年 | 12篇 |
2023年 | 114篇 |
2022年 | 153篇 |
2021年 | 250篇 |
2020年 | 293篇 |
2019年 | 327篇 |
2018年 | 299篇 |
2017年 | 338篇 |
2016年 | 377篇 |
2015年 | 309篇 |
2014年 | 456篇 |
2013年 | 748篇 |
2012年 | 668篇 |
2011年 | 615篇 |
2010年 | 489篇 |
2009年 | 641篇 |
2008年 | 722篇 |
2007年 | 655篇 |
2006年 | 637篇 |
2005年 | 551篇 |
2004年 | 515篇 |
2003年 | 471篇 |
2002年 | 410篇 |
2001年 | 305篇 |
2000年 | 326篇 |
1999年 | 272篇 |
1998年 | 223篇 |
1997年 | 214篇 |
1996年 | 199篇 |
1995年 | 143篇 |
1994年 | 135篇 |
1993年 | 125篇 |
1992年 | 90篇 |
1991年 | 86篇 |
1990年 | 52篇 |
1989年 | 32篇 |
1988年 | 41篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1984年 | 32篇 |
1983年 | 16篇 |
1982年 | 26篇 |
1981年 | 35篇 |
1980年 | 23篇 |
1979年 | 9篇 |
1978年 | 12篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
81.
本文得到Cn中有界域上全纯函数的一种其积分密度函数含有全纯函数导数的 Cauchy-Fantappi 公式,称之为第Ⅰ型 C-F 公式,利用这个公式,通过适当选择其中的向量函数,可以得到许多区域上全纯函数相应的第Ⅰ型积分表示式. 相似文献
82.
Matrix-Investigations on Monomeric Copper(I) Chloride and its Complexes with N2 and PN Ligands. IR Spectroscopic Results and ab-initio Calculation In solid argon the reaction of monomeric CuCl with N2 yields ClCuN2. On the basis of two absorptions in the ir-spectrum and their corresponding isotopic shifts (14/15N) and with the help of a normal coordinate analysis, linearity of the molecule has been deduced. These results are confirmed by large scale ab-initio Calculations (CPF, MP2). Reaction of monomeric CuCl with molecular PN under matrix condition is shown to give rise to new absorptions in the IR spectrum which arev assigned to a linear molecule ClCuNP. 相似文献
83.
利用K-泛函研究了修正的Baskakov型算子的Stechin-Marchaud型不等式,由此不等式,我们得到了关于ω2φλ的逆结果. 相似文献
84.
设D是一个Jordan,Г为其边界,并设Г满足Aльпер条件。本文得到了一种基于Fejer点的有理型插值算子对于f(z)∈C(Г)的一致逼近阶。 相似文献
85.
M. C. Jones 《Annals of the Institute of Statistical Mathematics》2004,56(4):733-742
A simple new family of distributions is proposed which has support the unit disc in two dimensions. The density functions
of the family are unimodal, monotonic or uniantimodal. The bivariate symmetric beta distributions, which include the uniform
distribution, are special cases, but many members of the family are skew. The distributions have three parameters, one controlling
orientation, one controlling degree of concentration and the third controlling skewness, or more precisely off-centredness.
Importantly, these parameters are globally orthogonal. An illustrative example of fitting the model to data is given. Conditional
and marginal distributions are considered. The new distributions are compared favourably with an earlier suggestion of the
same author. 相似文献
86.
聚乙二醇(PEG)6000经亚氨基二乙酸(IDA)修饰后和CuSO4反应,形成PEG修饰聚合物PEG-(IDA-Cu)2 ,与吐温80、磷酸盐混合,构成液-固亲和萃取体系,直接从大豆蛋白匀浆中提取氨基酸.选定萃取条件为磷酸盐摩尔比n(K2HPO4)∶n(NaH2PO4)为4.8∶1,体系pH值 7.70,总盐浓度为1.60 mol·L-1;吐温80的体积分数为10.5%.结果表明该体系对大豆蛋白匀浆中氨基酸的二次萃取率为66.5%,用离子交换技术后继处理,得纯度较高的组氨酸. 相似文献
87.
Michael Szydlo 《Journal of Number Theory》2004,104(1):75-99
Kodaira and Néron classified and described the geometry of the special fibers of the Néron model of an elliptic curve defined over a discrete valuation ring with a perfect residue field. Tate described an algorithm to determine the special fiber type by manipulating the Weierstrass equation. In the case of non-perfect residue fields, we discover new fiber types which are not on the Kodaira-Néron list. We describe these new types and extend Tate's algorithm to deal with all discrete valuation rings. Specifically, we show how to translate a Weierstrass equation into a form where the reduction type may be easily determined. Having determined the special fiber type, we construct the regular model of the curve with explicit blow-up calculations. We also provide tables that serve as a simple reference for the algorithm and which succinctly summarize the results. 相似文献
88.
H. Petersson 《Acta Mathematica Hungarica》2003,100(1-2):69-81
The PDE-preserving operators O on the space of nuclearly entire functions of bounded type HNb(E) on a Banach space E are characterized. An operator is PDE-preserving when it preserves homogenous solutions to homogeneous convolution equations.
We establish a one to one correspondence between O and a set Σ of sequences of entire functionals, i.e. exponential type functions. In this way, algebraic structures on Σ,
such as ring structures, can be carried over to O and vice versa. In particular, it follows that O is a non-commutative ring (algebra) with unity with respect to composition and the convolution operators form a commutative
subring (subalgebra). We discuss range and kernel properties, for the operators in O, and characterize the projectors (onto polynomial spaces) in O by determining the corresponding elements in Σ.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
89.
无机纳米粒子作为生物探针在生物分析中的研究进展 总被引:3,自引:0,他引:3
介绍了无机纳米粒子在生物分析领域的研究进展分别从生物分子与纳米粒子的耦联方式、检测生物分子的纳米金探针、核酸或蛋白质修饰的其它纳米探针以及生物纳米技术的应用前景4个方面对该领域的发展进行了概述。 相似文献
90.
We solve the problem of describing compatible nonlocal Poisson brackets of hydrodynamic type. We prove that for nonsingular pairs of compatible nonlocal Poisson brackets of hydrodynamic type, there exist special local coordinates such that the metrics and the Weingarten operators of both brackets are diagonal. The nonlinear evolution equations describing all nonsingular pairs of compatible nonlocal Poisson brackets of hydrodynamic type are derived in these special coordinates, and the integrability of these equations is proved using the inverse scattering transform. The Lax pairs with a spectral parameter for these equations are found. We construct various classes of integrable reductions of the derived equations. These classes of reductions are of an independent differential-geometric and applied interest. In particular, if one of the compatible Poisson brackets is local, we obtain integrable reductions of the classical Lamé equations describing all orthogonal curvilinear coordinate systems in a flat space; if one of the compatible brackets is generated by a constant-curvature metric, the corresponding equations describe integrable reductions of the equations for orthogonal curvilinear coordinate systems in a space of constant curvature. 相似文献