全文获取类型
收费全文 | 7989篇 |
免费 | 996篇 |
国内免费 | 430篇 |
专业分类
化学 | 570篇 |
晶体学 | 45篇 |
力学 | 1210篇 |
综合类 | 162篇 |
数学 | 5475篇 |
物理学 | 1953篇 |
出版年
2025年 | 34篇 |
2024年 | 121篇 |
2023年 | 111篇 |
2022年 | 102篇 |
2021年 | 111篇 |
2020年 | 228篇 |
2019年 | 214篇 |
2018年 | 203篇 |
2017年 | 264篇 |
2016年 | 235篇 |
2015年 | 207篇 |
2014年 | 387篇 |
2013年 | 616篇 |
2012年 | 536篇 |
2011年 | 543篇 |
2010年 | 390篇 |
2009年 | 437篇 |
2008年 | 491篇 |
2007年 | 449篇 |
2006年 | 412篇 |
2005年 | 380篇 |
2004年 | 311篇 |
2003年 | 323篇 |
2002年 | 291篇 |
2001年 | 248篇 |
2000年 | 228篇 |
1999年 | 224篇 |
1998年 | 224篇 |
1997年 | 190篇 |
1996年 | 128篇 |
1995年 | 100篇 |
1994年 | 105篇 |
1993年 | 73篇 |
1992年 | 58篇 |
1991年 | 38篇 |
1990年 | 43篇 |
1989年 | 29篇 |
1988年 | 32篇 |
1987年 | 30篇 |
1986年 | 30篇 |
1985年 | 28篇 |
1984年 | 38篇 |
1983年 | 17篇 |
1982年 | 35篇 |
1981年 | 27篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 14篇 |
1976年 | 10篇 |
1973年 | 8篇 |
排序方式: 共有9415条查询结果,搜索用时 15 毫秒
181.
Consider the Bayes problem in which one has to discriminate if the random unknown initial state of a stochastic process is distributed according to either of two preassigned distributions, on the base of the observation of the first‐passage time of the process through 0. For processes whose first‐passage times to state 0 are increasing in the initial state according to the likelihood ratio order, such problem is solved by determining the Bayes decision function and the corresponding Bayes error. The special case of fixed initial values including a family of first‐passage times with proportional reversed hazard functions is then studied. Finally, various applications to birth‐and‐death and to diffusion processes are discussed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
182.
In this paper we prove an existence theorem for the Cauchy problem
using the Henstock-Kurzweil-Pettis integral and its properties. The requirements on the function f are not too restrictive: scalar measurability and weak sequential continuity with respect to the second variable. Moreover, we suppose that the function f satisfies some conditions expressed in terms of measures of weak noncompactness. 相似文献
183.
For each sN define the constant θs with the following properties: if an entire function g(z) of type t(g)<θs satisfies then g is a polynomial; conversely, for any δ>0 there exists an entire transcendental function g(z) satisfying the display conditin and t(g)<θs+δ. The result θ1=log2 is known due to Hardy and Pólya. We provide the upper bound θsπs/3 and improve earlier lower bounds due to Gelfond (1929) and Selberg (1941). 相似文献
184.
高进寿 《数学年刊A辑(中文版)》2004,(5)
设B是Cn中的单位球,S是Cn中的单位球面,Sα(f)是B上的面积积分.设f∈BMOA, 若存在正测度集E(?)S,使Sα(f)<∞在E上成立,则Sα(f)<∞在S上几乎处处成立,同时 Sα(f)∈ BMO(S)且存在常数C,使得||Sαf||*≤C||f||*. 相似文献
185.
De-haoYu 《计算数学(英文版)》2004,22(2):309-318
In this paper, the natural boundary integral method, and some related methods, including coupling method of the natural boundary elements and finite elements, which is also called DtN method or the method with exact artificial boundary conditions, domain decomposition methods based on the natural boundary reduction, and the adaptive boundary element method with hyper-singular a posteriori error estimates, are discussed. 相似文献
186.
N. N. Romanovskii 《Siberian Mathematical Journal》2008,49(1):155-165
We consider one class of singular integral operators over the functions on domains of Carnot groups. We prove the L p boundedness, 1 < p > ∞, for the operators of this class. Similar operators over the functions on domains of Euclidean space were considered by Mikhlin. 相似文献
187.
Dimitrios Betsakos 《Mathematische Zeitschrift》2008,259(1):187-196
Let denote the density of the hyperbolic metric for a domain Ω in the extended complex plane . We prove the inequality
with C = 8.27. The inequality was proved by Sugawa and Vuorinen with C = 10.33. The proof uses monotonicity properties of the hyperbolic metric for the thrice punctured extended plane. Gardiner
and Lakic proved the inequality
with an unspecified constant C
1. We show that the best constant Σ1 in this inequality is between 3.25 and 8.27. We also prove a related conjecture formulated by Sugawa and Vuorinen.
The author was partially supported by the EPEAK programm Pythagoras II (Greece). 相似文献
188.
An M/GI/1 queueing system is in series with a unit with negative exponential service times and infinite waiting room capacity. We determine a closed form expression for the generating function of the joint queue length distribution in steady state. This result is obtained via the solution of a new type of functional equation in two variables. 相似文献
189.
L. Brutman 《Numerical Algorithms》1993,5(9):437-442
Generalized alternating polynomials have been introduced by the author earlier. In the present paper their indirect analogue is constructed for numerical solution of the Fredholm linear integral equations. Although the proposed method is a particular case of the general projection scheme, its valuable feature is the presence of a sequence of parameters, which, for sufficiently smooth kernels and inhomogeneous terms, serves as an indicator of the quality of approximation. 相似文献
190.
Márcia Federson 《Czechoslovak Mathematical Journal》2002,52(2):429-437
We prove two versions of the Monotone Convergence Theorem for the vector integral of Kurzweil,
, where R is a compact interval of
, and f are functions with values on L(Z,W) and Z respectively, and Z and W are monotone ordered normed spaces. Analogous results can be obtained for the Kurzweil vector integral,
, as well as to unbounded intervals R. 相似文献