全文获取类型
收费全文 | 1145篇 |
免费 | 36篇 |
国内免费 | 3篇 |
专业分类
化学 | 852篇 |
晶体学 | 8篇 |
力学 | 7篇 |
数学 | 105篇 |
物理学 | 212篇 |
出版年
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 20篇 |
2019年 | 15篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 28篇 |
2015年 | 16篇 |
2014年 | 26篇 |
2013年 | 53篇 |
2012年 | 55篇 |
2011年 | 68篇 |
2010年 | 29篇 |
2009年 | 35篇 |
2008年 | 66篇 |
2007年 | 68篇 |
2006年 | 42篇 |
2005年 | 63篇 |
2004年 | 45篇 |
2003年 | 71篇 |
2002年 | 52篇 |
2001年 | 13篇 |
2000年 | 18篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 9篇 |
1994年 | 16篇 |
1993年 | 8篇 |
1992年 | 19篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 8篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 23篇 |
1984年 | 25篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1979年 | 15篇 |
1978年 | 16篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 4篇 |
排序方式: 共有1184条查询结果,搜索用时 15 毫秒
81.
In this paper we are concerned with solutions, in particular with univalent solutions, of the Loewner differential equation
associated with non-normalized subordination chains on the Euclidean unit ball B
n
in
\mathbbCn{\mathbb{C}^n}. The main result is a generalization to higher dimensions of a well known result due to Becker. Various particular cases
of this result have been recently obtained for subordination chains with normalization Df(0,t)=etIn{Df(0,t)=e^tI_n} or Df(0, t) = e
tA
, t ≥ 0, where
A ? L(\mathbbCn,\mathbbCn){A\in L(\mathbb{C}^n,\mathbb{C}^n)}. We also determine the form of the standard solutions to the Loewner differential equation associated with generalized spirallike
mappings. In the last section we obtain the form of the solution in the presence of coefficient bounds. 相似文献
82.
Hidetaka Hamada 《Journal of Geometric Analysis》1998,8(3):441-446
The purpose of this paper is to prove that every proper holomorphic self-mapping of a Reinhardt domain Ω in
C
n
which is a generalization of a complex ellipsoid is biholomorphic. The main novelty of our result is that Ω is a domain in
C
n
such that it is allowed to have a boundary point at which the Levi determinant has infinite order of vanishing. 相似文献
83.
It has been shown by Bogdanova and Boukliev [1] that there exist a ternary [38,5,24] code and a ternary [37,5,23] code. But it is unknown whether or not there exist a ternary [39,6,24] code and a ternary [38,6,23] code. The purpose of this paper is to prove that (1) there is no ternary [39,6,24] code and (2) there is no ternary [38,6,23] code using the nonexistence of ternary [39,6,24] codes. Since it is known (cf. Brouwer and Sloane [2] and Hamada and Watamori [14]) that (i) n3(6,23) = 38> or 39 and d3(38,6) = 22 or 23 and (ii) n3(6,24) = 39 or 40 and d3(39,6) = 23 or 24, this implies that n3(6,23) = 39, d3(38,6) = 22, n3(6,24) = 40 and d3(39,6) = 23, where n3<>(k,d) and d<>3(n,k) denote the smallest value of n and the largest value of d, respectively, for which there exists an [n,k,d] code over the Galois field GF(3). 相似文献
84.
Let nq(k, d) denote the smallest value of n for which there exists an [n, k, d; q]-code. It is known (cf. (J. Combin. Inform. Syst. Sci.18, 1993, 161–191)) that (1) n3(6, 195) {294, 295}, n3(6, 194) {293, 294}, n3(6, 193) {292, 293}, n3(6, 192) {290, 291}, n3(6, 191) {289, 290}, n3(6, 165) {250, 251} and (2) there is a one-to-one correspondence between the set of all nonequivalent [294, 6, 195; 3]-codes meeting the Griesmer bound and the set of all {v2 + 2v3 + v4, v1 + 2v2 + v3; 5, 3}-minihypers, where vi = (3i − 1)/(3 − 1) for any integer i ≥ 0. The purpose of this paper is to show that (1) n3(6, 195) = 294, n3(6, 194) = 293, n3(6, 193) = 292, n3(6, 192) = 290, n3(6, 191) = 289, n3(6, 165) = 250 and (2) a [294, 6, 195; 3]-code is unique up to equivalence using a characterization of the corresponding {v2 + 2v3 + v4, v1 + 2v2 + v3; 5, 3}-minihypers. 相似文献
85.
Letf(z, t) be a subordination chain fort ∈ [0, α], α>0, on the Euclidean unit ballB inC
n. Assume thatf(z) =f(z, 0) is quasiconformal. In this paper, we give a sufficient condition forf to be extendible to a quasiconformal homeomorphism on a neighbourhood of
. We also show that, under this condition,f can be extended to a quasiconformal homeomorphism of
onto itself and give some applications.
Partially supported by Grant-in-Aid for Scientific Research (C) no. 14540195 from Japan Society for the Promotion of Science,
2004. 相似文献
86.
In this article we deal with a multi-dimensional diffusion whose corresponding diffusion vector fields are commutative, and study its joint distribution at the time when a component attains its maximum on finite time interval. Under regularity and ellipticity conditions we shall show the smoothness of this joint distribution. 相似文献
87.
Masafumi Yoshino 《偏微分方程通讯》2013,38(9-10):1925-1950
We study the global solvability of Monge-Ampère equations of mixed type by "blowing up" the problem onto the torus embedded at the singular point of the equations 相似文献
88.
This paper considers the pricing of contingent claims using an approach developed and used in insurance pricing. The approach is of interest and significance because of the increased integration of insurance and financial markets and also because insurance-related risks are trading in financial markets as a result of securitization and new contracts on futures exchanges. This approach uses probability distortion functions as the dual of the utility functions used in financial theory. The pricing formula is the same as the Black-Scholes formula for contingent claims when the underlying asset price is log-normal. The paper compares the probability distortion function approach with that based on financial theory. The theory underlying the approaches is set out and limitations on the use of the insurance-based approach are illustrated. The probability distortion approach is extended to the pricing of contingent claims for more general assumptions than those used for Black-Scholes option pricing. 相似文献
89.
Hirofumi Okuda Shigeru Matsushima Hideshi Sugiura Kenji Yamada Shunsuke Hamada Yoshihiro Nishida Naoki Ishiguro 《Magnetic resonance imaging》2014
Objective
Equivalent cross-relaxation rate imaging (ECRI) is an MRI technique used to evaluate qualitative changes in protein-water interactions. We aimed to prospectively evaluate the utility of ECRI for classification of adipocytic tumors.Materials and Methods
Institutional Review Board approval was obtained and all patients provided informed consent. Study participants included 40 patients with adipocytic tumors who were diagnosed with lipomas (n = 22), atypical lipomatous tissue/well-differentiated liposarcoma (ALT/WDL; n = 9), myxoid/round cell liposarcoma (MyL; n = 6), and dedifferentiated liposarcoma (DDL; n = 3), and 20 control patients for whom subcutaneous fat in the buttock or thigh was analyzed.Results
Mean ECR values of lipomas, ALT/WDL, and subcutaneous fat were low, and those of MyL and DDL were high. Mean ECR values of MyL and DDL were significantly higher than those of ALT/WDL. The cut-off value was 5.1%. There was a positive correlation between ECR value, pathological grade, and cell density in adipocytic tumors.Conclusion
The ECR value positively correlates with pathological grade and cell density of adipocytic tumors. Our findings suggest that ECRI is a useful method for preoperative evaluation of adipocytic tumors. 相似文献90.