全文获取类型
收费全文 | 10063篇 |
免费 | 311篇 |
国内免费 | 359篇 |
专业分类
化学 | 2043篇 |
晶体学 | 37篇 |
力学 | 131篇 |
综合类 | 44篇 |
数学 | 7410篇 |
物理学 | 1068篇 |
出版年
2023年 | 56篇 |
2022年 | 211篇 |
2021年 | 199篇 |
2020年 | 131篇 |
2019年 | 286篇 |
2018年 | 307篇 |
2017年 | 144篇 |
2016年 | 118篇 |
2015年 | 163篇 |
2014年 | 361篇 |
2013年 | 642篇 |
2012年 | 471篇 |
2011年 | 748篇 |
2010年 | 642篇 |
2009年 | 831篇 |
2008年 | 809篇 |
2007年 | 782篇 |
2006年 | 602篇 |
2005年 | 381篇 |
2004年 | 345篇 |
2003年 | 319篇 |
2002年 | 237篇 |
2001年 | 207篇 |
2000年 | 167篇 |
1999年 | 224篇 |
1998年 | 158篇 |
1997年 | 117篇 |
1996年 | 143篇 |
1995年 | 137篇 |
1994年 | 131篇 |
1993年 | 104篇 |
1992年 | 71篇 |
1991年 | 60篇 |
1990年 | 42篇 |
1989年 | 50篇 |
1988年 | 26篇 |
1987年 | 25篇 |
1986年 | 30篇 |
1985年 | 27篇 |
1984年 | 32篇 |
1983年 | 13篇 |
1982年 | 25篇 |
1981年 | 37篇 |
1980年 | 28篇 |
1979年 | 23篇 |
1978年 | 15篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1974年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
Brenton R. Clarke 《Journal of multivariate analysis》2007,98(5):916-931
In this paper, we consider the estimation of a parameter of interest where the estimator is one of the possibly several solutions of a set of nonlinear empirical equations. Since Newton's method is often used in such a setting to obtain a solution, it is important to know whether the so obtained iteration converges to the locally unique consistent root to the aforementioned parameter of interest. Under some conditions, we show that this is eventually the case when starting the iteration from within a ball about the true parameter whose size does not depend on n. Any preliminary almost surely consistent estimate will eventually lie in such a ball and therefore provides a suitable starting point for large enough n. As examples, we will apply our results in the context of M-estimates, kernel density estimates, as well as minimum distance estimates. 相似文献
93.
有限维路代数的K_1群 总被引:1,自引:0,他引:1
本文通过计算有限维路代数k△的单位群和单位群的阿贝尔化,完全刻划了 任意域上有限维路代数的K1群. 相似文献
94.
Dragos Ghioca 《Journal of Number Theory》2007,125(1):85-94
We study the v-adic distance from the torsion of a Drinfeld module to an affine variety. 相似文献
95.
We give several new constructions for moderate rank elliptic curves over Q(T). In particular we construct infinitely many rational elliptic surfaces (not in Weierstrass form) of rank 6 over Q using polynomials of degree two in T. While our method generates linearly independent points, we are able to show the rank is exactly 6 without having to verify the points are independent. The method generalizes; however, the higher rank surfaces are not rational, and we need to check that the constructed points are linearly independent. 相似文献
96.
Jon Wilkening 《Linear algebra and its applications》2007,427(1):6-25
We present an efficient algorithm for obtaining a canonical system of Jordan chains for an n × n regular analytic matrix function A(λ) that is singular at the origin. For any analytic vector function b(λ), we show that each term in the Laurent expansion of A(λ)−1b(λ) may be obtained from the previous terms by solving an (n + d) × (n+d) linear system, where d is the order of the zero of det A(λ) at λ = 0. The matrix representing this linear system contains A(0) as a principal submatrix, which can be useful if A(0) is sparse. The last several iterations can be eliminated if left Jordan chains are computed in addition to right Jordan chains. The performance of the algorithm in floating point and exact (rational) arithmetic is reported for several test cases. The method is shown to be forward stable in floating point arithmetic. 相似文献
97.
Ignacio Villanueva 《Mathematische Nachrichten》2003,250(1):98-103
We clarify and prove in a simpler way a result of Taskinen about symmetric operators on C(Kn), K an uncountable metrizable compact space. To do this we prove that, for any compact space K and any n ∈ ?, the symmetric injective n–tensor product of C(K), , is complemented in C(BC(K)*), a result of independent interest. The techniques we develop allow us to extend the result in several directions. We also show that the hypothesis of metrizability and uncountability cannot be removed. 相似文献
98.
教师课堂教学质量的多元统计分析 总被引:3,自引:0,他引:3
应用多元统计分析中的聚类分析法和主成分分析法对教师高等数学的课堂教学质量进行了统计分析,通过对数据的聚类分析结果提出教师应注重启发性教学并善于引导学生解决实际问题.同时利用主成分分析将原先众多的评价指标用三个指标代替,为进一步提高教学质量提供科学的依据. 相似文献
99.
We investigate differential operators and their compatibility with subgroups of SL2n(R). In particular, we construct Rankin-Cohen brackets for Hilbert modular forms, and more generally, multilinear differential operators on the space of Hilbert modular forms. As an application, we explicitly determine the Rankin-Cohen bracket of a Hilbert-Eisenstein series and an arbitrary Hilbert modular form. We use this result to compute the Petersson inner product of such a bracket and a Hilbert modular cusp form. 相似文献
100.
J. Haglund 《Advances in Mathematics》2003,175(2):319-334
We introduce the distribution function Fn(q,t) of a pair of statistics on Catalan words and conjecture Fn(q,t) equals Garsia and Haiman's q,t-Catalan sequence Cn(q,t), which they defined as a sum of rational functions. We show that Fn,s(q,t), defined as the sum of these statistics restricted to Catalan words ending in s ones, satisfies a recurrence relation. As a corollary we are able to verify that Fn(q,t)=Cn(q,t) when t=1/q. We also show the partial symmetry relation Fn(q,1)=Fn(1,q). By modifying a proof of Haiman of a q-Lagrange inversion formula based on results of Garsia and Gessel, we obtain a q-analogue of the general Lagrange inversion formula which involves Catalan words grouped according to the number of ones at the end of the word. 相似文献