全文获取类型
收费全文 | 446篇 |
免费 | 10篇 |
国内免费 | 7篇 |
专业分类
化学 | 210篇 |
晶体学 | 3篇 |
力学 | 13篇 |
数学 | 134篇 |
物理学 | 71篇 |
无线电 | 32篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 18篇 |
2013年 | 23篇 |
2012年 | 19篇 |
2011年 | 21篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 32篇 |
2007年 | 32篇 |
2006年 | 25篇 |
2005年 | 18篇 |
2004年 | 25篇 |
2003年 | 21篇 |
2002年 | 17篇 |
2001年 | 14篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有463条查询结果,搜索用时 15 毫秒
51.
We show that short range order models relate the multiplicity distribution produced in a rapidity interval R of the central region, to the distribution of such intervals which all contain a fixed multiplicity N. This is an asymptotic result which furthermore implies that the asymptotic behavior of the Mueller moments be related to certain rapidity gap correlation moments. The behavior of these gap correlations in specific models depends in a direct way on the assumptions made about clustering and about the range of the interaction. 相似文献
52.
Several variants of the modal interpretation of quantum mechanics have been introduced and discussed in recent years. In this paper we present a study of the mathematical foundations of such an interpretation in the framework of the quantum theory of measurement. 相似文献
53.
Pekka Korhonen Margareta Soismaa 《The Journal of the Operational Research Society》1981,32(7):577-585
In this paper we are concerned with ranking various orderings of a set of alternatives to a composite order as a multiple criteria problem. The orderings (called preference orderings) can be real preference orderings or any natural orderings. The objective is to find the most preferred order of the decision maker using the preference orderings as criteria.In principle, the problem can be formulated as a multiple objective linear programming problem using the model of Bowman and Colantoni and then solved with the interactive method proposed by Zionts and Wallenius. However, the fact that we are dealing with integer variables prohibits us from applying this approach as such. We discuss the problem formulation and propose a modified approach to that of Zionts and Wallenius for solving the problem. 相似文献
54.
55.
Let be a domain. Suppose that f ∈ W1,1loc(Ω,R2) is a homeomorphism such that Df(x) vanishes almost everywhere in the zero set of Jf. We show that f-1 ∈ W1,1loc(f(Ω),R2) and that Df−1(y) vanishes almost everywhere in the zero set of Sharp conditions to quarantee that f−1 ∈ W1,q(f(Ω),R2) for some 1<q≤2 are also given. 相似文献
56.
[reaction: see text] Cobalt catalysis enables a new method for the generation of zinc enolates using diethylzinc to reduce alpha,beta-unsaturated amides. This method has been applied to a high-yielding diastereoselective reductive aldol cyclization. 相似文献
57.
Jussi Laitila Pekka J. Nieminen Eero Saksman Hans-Olav Tylli 《Complex Analysis and Operator Theory》2013,7(1):163-181
Any analytic map φ of the unit disc ${\mathbb{D}}$ into itself induces a composition operator C φ on BMOA, mapping ${f \mapsto f \circ \varphi}$ , where BMOA is the Banach space of analytic functions ${f\colon \mathbb{D} \to \mathbb{C}}$ whose boundary values have bounded mean oscillation on the unit circle. We show that C φ is weakly compact on BMOA precisely when it is compact on BMOA, thus solving a question initially posed by Tjani and by Bourdon, Cima and Matheson in the special case of VMOA. As a crucial step of our argument we simplify the compactness criterion due to Smith for C φ on BMOA and show that his condition on the Nevanlinna counting function alone characterizes compactness. Additional equivalent compactness criteria are established. Furthermore, we prove the unexpected result that compactness of C φ on VMOA implies compactness even from the Bloch space into VMOA. 相似文献
58.
Children differ in how much they spontaneously pay attention to quantitative aspects of their natural environment. We studied how this spontaneous tendency to focus on numerosity (SFON) is related to subitizing-based enumeration and verbal and object counting skills. In this exploratory study, children were tested individually at the age of 4–5 years on these skills. Results showed 2 primary relationships in children's number skills development. Performance in a number sequence production task, which is closely related to ordinal number sequence without reference to cardinality, is directly associated with SFON. Second, the association of SFON and object counting skills, which require relating cardinal and ordinal aspects of number, is mediated by subitizing-based enumeration. This suggests that there are multiple pathways to enumeration skills during development. 相似文献
59.
The present study was conducted to investigate the molecular absorption by AlCl in a carbon rod furnace for determination of chlorine in organic compounds, by using the lead atomic line at 261.418 nm emitted from a Pb-hollow cathode lamp. A deuterium lamp was used for the simultaneous background correction. The method enables rapid and accurate determination of trace chlorine in varying organic samples with good precision. The method was tested on different organic chloro-coumpounds and α-pinene products. 相似文献
60.