全文获取类型
收费全文 | 93069篇 |
免费 | 5043篇 |
国内免费 | 12459篇 |
专业分类
化学 | 74393篇 |
晶体学 | 1207篇 |
力学 | 2355篇 |
综合类 | 881篇 |
数学 | 12700篇 |
物理学 | 19035篇 |
出版年
2024年 | 85篇 |
2023年 | 654篇 |
2022年 | 1596篇 |
2021年 | 1838篇 |
2020年 | 2251篇 |
2019年 | 2205篇 |
2018年 | 1921篇 |
2017年 | 2784篇 |
2016年 | 2913篇 |
2015年 | 2429篇 |
2014年 | 3421篇 |
2013年 | 6968篇 |
2012年 | 6357篇 |
2011年 | 5119篇 |
2010年 | 4291篇 |
2009年 | 5924篇 |
2008年 | 6106篇 |
2007年 | 6364篇 |
2006年 | 5765篇 |
2005年 | 4926篇 |
2004年 | 4589篇 |
2003年 | 3802篇 |
2002年 | 5017篇 |
2001年 | 2911篇 |
2000年 | 2720篇 |
1999年 | 2531篇 |
1998年 | 2205篇 |
1997年 | 1744篇 |
1996年 | 1491篇 |
1995年 | 1428篇 |
1994年 | 1275篇 |
1993年 | 1067篇 |
1992年 | 1014篇 |
1991年 | 662篇 |
1990年 | 562篇 |
1989年 | 540篇 |
1988年 | 401篇 |
1987年 | 308篇 |
1986年 | 299篇 |
1985年 | 234篇 |
1984年 | 242篇 |
1983年 | 142篇 |
1982年 | 219篇 |
1981年 | 190篇 |
1980年 | 209篇 |
1979年 | 192篇 |
1978年 | 172篇 |
1977年 | 127篇 |
1976年 | 112篇 |
1973年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
81.
S.-Y. Sheu D.-Y. Yang H.L. Selzle E.W. Schlag 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(3):557-563
Charge transport is one important example of signal transduction in a protein which is responsible for action at a distance,
and is a fundamental process in biochemical action. A model is presented in which electronic effects interact with motional
processes to combine into a bifunctional model. This model is investigated with new detailed molecular dynamics calculations
and successfully explains such action at a distance.
Received 1st February 2002 / Received in final form 26 May 2002 Published online 13 September 2002 相似文献
82.
阐述检测物体是否产生了电场的方法;通过实际检测证实立方体永磁体既产生了负静电场,也产生了正静电场,并测定了具体的场强. 相似文献
83.
meso-Tetra(n-hexyloxycarbonyl)porphyrin was found to be converted into porphine, the mother compound of porphyrins, in a 77% yield when heated in aqueous sulfuric acid at 180 °C over 30 min under an inert atmosphere. The observation demonstrates that the substituted porphyrin serves as a novel and useful precursor for porphine. 相似文献
84.
85.
We obtain upper bounds for the tail distribution of the first nonnegative sum of a random walk and for the moments of the overshoot over an arbitrary nonnegative level if the expectation of jumps is positive and close to zero. In addition, we find an estimate for the expectation of the first ladder epoch. 相似文献
86.
87.
Kasper K. Berthelsen Jesper Møller 《Bulletin of the Brazilian Mathematical Society》2002,33(3):351-367
This primer provides a self-contained exposition of the case where spatial birth-and-death processes are used for perfect
simulation of locally stable point processes. Particularly, a simple dominating coupling from the past (CFTP) algorithm and
the CFTP algorithms introduced in [13], [14], and [5] are studied. Some empirical results for the algorithms are discussed.
Received: 30 June 2002 相似文献
88.
89.
Let G=(V(G),E(G)) be a graph. A (n,G, λ)‐GD is a partition of the edges of λKn into subgraphs (G‐blocks), each of which is isomorphic to G. The (n,G,λ)‐GD is named as graph design for G or G‐decomposition. The large set of (n,G,λ)‐GD is denoted by (n,G,λ)‐LGD. In this work, we obtain the existence spectrum of (n,P3,λ)‐LGD. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 151–159, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10008 相似文献
90.
A design of diode-pumped high-efficiency Nd:YVO4/LBO red laser is reported. Using critical phase-matching (CPM) LBO, 671 nm red laser was obtained from 1342 nm light by intracavity frequency doubling. With an incident pump laser of 800 mW, using type-I and type-II CPM LBO, 97 and 52 mWTEM00 mode red laser outputs were obtained, with optical-to-optical conversion efficiencies of up to 12.1% and 6.5%, respectively. 相似文献