全文获取类型
收费全文 | 1721篇 |
免费 | 47篇 |
国内免费 | 12篇 |
专业分类
化学 | 1067篇 |
晶体学 | 6篇 |
力学 | 47篇 |
数学 | 271篇 |
物理学 | 389篇 |
出版年
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 14篇 |
2020年 | 31篇 |
2019年 | 34篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 39篇 |
2015年 | 30篇 |
2014年 | 40篇 |
2013年 | 76篇 |
2012年 | 62篇 |
2011年 | 85篇 |
2010年 | 53篇 |
2009年 | 48篇 |
2008年 | 79篇 |
2007年 | 76篇 |
2006年 | 82篇 |
2005年 | 84篇 |
2004年 | 68篇 |
2003年 | 69篇 |
2002年 | 51篇 |
2001年 | 24篇 |
2000年 | 23篇 |
1999年 | 27篇 |
1998年 | 18篇 |
1997年 | 9篇 |
1996年 | 19篇 |
1995年 | 11篇 |
1994年 | 18篇 |
1993年 | 19篇 |
1992年 | 15篇 |
1991年 | 17篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1986年 | 10篇 |
1985年 | 27篇 |
1984年 | 24篇 |
1983年 | 26篇 |
1982年 | 41篇 |
1981年 | 33篇 |
1980年 | 24篇 |
1979年 | 14篇 |
1978年 | 21篇 |
1977年 | 11篇 |
1976年 | 16篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 13篇 |
1965年 | 9篇 |
排序方式: 共有1780条查询结果,搜索用时 15 毫秒
1.
Leo Liebermann 《Fresenius' Journal of Analytical Chemistry》1883,22(1):232-233
Ohne Zusammenfassung 相似文献
2.
3.
Stefano De Leo 《International Journal of Theoretical Physics》1996,35(9):1821-1837
We derive an appropriate definition of transpose for quaternionic matrices and give a new panoramic review of the quaternionic groups. We aim to analyze possible quaternionic groups for GUTs. 相似文献
4.
5.
B. Savo P. Romano A. Nigro R. Di Leo 《Physica C: Superconductivity and its Applications》2002,370(4):275-280
The flat voltage noise component of current biased, high-transparency Nb/AlOx/Nb superconducting tunnel junctions has been investigated at frequencies up to 70 kHz. Several aspects of the analyzed phenomena suggest the presence of current noise effects induced by the discreteness of the charge carriers. At subgap voltages, where excess currents occur, a behavior coherent with a multiple Andreev reflection-assisted transport through the tunnel barrier has been found. However, the measured charge values exceed any theoretical prediction. 相似文献
6.
Monica-Gabriela Cojocaru Leo B. Jonker 《Proceedings of the American Mathematical Society》2004,132(1):183-193
We prove existence and uniqueness of integral curves to the (discontinuous) vector field that results when a Lipschitz continuous vector field on a Hilbert space of any dimension is projected on a non-empty, closed and convex subset.
7.
An approach called Schramm–Loewner evolution (SLE) provides a new method for dealing with a wide variety of scale-invariant problems in two dimensions. This approach is based upon an older method called Loewner Evolution (LE), which connects analytic and geometrical constructions in the complex plane. In this paper, the bases of LE and SLE are described and some simple applications are discussed in relatively non-technical form. A bibliography of the subject is presented. 相似文献
8.
9.
Leo Brewin 《General Relativity and Gravitation》2007,39(4):521-528
We show by an almost elementary calculation that the ADM mass of an asymptotically flat space can be computed as a limit involving
a rate of change of area of a closed 2-surface. The result is essentially the same as that given by David Brown and York (Phys.
Rev. D 55, 1977–1984 1997; Phys. Rev. D 47, 1407–1419 1993). We will prove this result in two ways, first by direct calculation from the original formula as given by
Arnowitt, Deser and Misner and second as a corollary of an earlier result by Brewin for the case of simplicial spaces. 相似文献
10.
In mountain-rescue operations injured people are generally exposed to vibrations and shocks that can be potential causes of physical conditions worsening. Such vibrations can derive both from patient's body manipulations (e.g. when it is being loaded and immobilized on a stretcher) and from forces coming from the transport devices and vehicles. Despite the general feeling that during this kind of operations the levels of transmitted vibrations to the injured can be quite large and potentially dangerous, there is practically no study in literature providing reliable parameters (i.e. measurements) to support or dismiss these beliefs. This paper reports the results of a measurement campaign carried-out in order to outline, identify and quantify the excitations a human body is exposed to, during typical transportation phases related to mountain-rescue operations. The work mainly presents and discusses the experimental setup with the aim of focusing on the problems related to this kind of measurements; the results of the experimental campaign carried-out for the measurement of the vibrations undergone by a human body during a simulated rescue operation are presented and discussed as well. Such simulation includes three phases of transportation: on a hand-held stretcher, on an ambulance and on a helicopter. The work is not intended to supply a complete characterization and analysis of vibrations transmission during any rescue operation but just to provide a preliminary overview and to define a measurement method that can be applied for a more comprehensive characterization. With such aims measurements were carried out in on-field situations stated as “typical” by rescue experts and data then analyzed both with standard procedures and algorithms (e.g. ISO 2631s weighting curves) and with the commonly used statistical indexes; in the analysis it is important to be aware that standardized measurement procedures and indexes, created to verify comfort or health-risks of workers, might not fit the case of a generic patient who experienced a serious mountain accident. The work includes also a laboratory activity mainly related to mechanical characterization of the stretcher used in the field tests. The most interesting result of the study is the comparison of the vibration levels in the various rescue phases that, even when using different indicators, shows that the most critical issue is due to hand transportation despite the bad judgment usually expressed for helicopter flight. 相似文献