全文获取类型
收费全文 | 1790篇 |
免费 | 83篇 |
国内免费 | 4篇 |
专业分类
化学 | 1459篇 |
晶体学 | 16篇 |
力学 | 19篇 |
数学 | 88篇 |
物理学 | 295篇 |
出版年
2023年 | 12篇 |
2022年 | 23篇 |
2021年 | 11篇 |
2020年 | 25篇 |
2019年 | 33篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 48篇 |
2015年 | 38篇 |
2014年 | 48篇 |
2013年 | 81篇 |
2012年 | 97篇 |
2011年 | 143篇 |
2010年 | 63篇 |
2009年 | 52篇 |
2008年 | 124篇 |
2007年 | 87篇 |
2006年 | 107篇 |
2005年 | 117篇 |
2004年 | 98篇 |
2003年 | 81篇 |
2002年 | 77篇 |
2001年 | 38篇 |
2000年 | 31篇 |
1999年 | 33篇 |
1998年 | 18篇 |
1997年 | 28篇 |
1996年 | 20篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 14篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 12篇 |
1982年 | 15篇 |
1981年 | 16篇 |
1980年 | 15篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1974年 | 6篇 |
1973年 | 7篇 |
排序方式: 共有1877条查询结果,搜索用时 15 毫秒
1.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
2.
Tsuyoshi Kitamura 《Tetrahedron》2004,60(43):9649-9657
Synthesis of (+)-anthramycin was examined. A pyrrolobenzodiazepine skeleton could be synthesized by reductive cyclization of pyrrolidine derivative, which was obtained by enyne metathesis. The conjugated enamide ester part of (+)-anthramycin derivative was constructed by cross-metathesis. 相似文献
3.
In this paper we consider the (t, n)-threshold visual secret sharing scheme (VSSS) in which black pixels in a secret black-white images is reproduced perfectly
as black pixels when we stack arbitrary t shares. This paper provides a new characterization of the (t, n)-threshold visual secret sharing scheme with such a property (hereafter, we call such a VSSS the (t, n)-PBVSSS for short). We use an algebraic method to characterize basis matrices of the (t, n)-PBVSSS in a certain class of matrices. We show that the set of all homogeneous polynomials each element of which yields
basis matrices of the (t, n)-PBVSSS becomes a set of lattice points in an (n−t+1)-dimensional linear space. In addition, we prove that the optimal basis matrices in the sense of maximizing the relative
difference among all the basis matrices in the class coincides with the basis matrices given by Blundo, Bonis and De Santis
[3] for all n≥ t ≥ 2. 相似文献
4.
5.
Tsuyoshi Katayama 《Queueing Systems》1992,11(3):299-306
This paper derives a conservation law for mean waiting times in a single-server multi-class service queueing system (M
X/G/1 type queue) with setup times which may be dependent on multiple customer classes and its arrival batch size by using the work decomposition property in the queueing system with vacations. 相似文献
6.
We investigate low-temperature behaviors of a system with chirality-pair interaction on a one-dimensional lattice. In the course of the investigation, we evaluate asymptotic forms of the characteristic values of the integral equation satisfied by the Mathieu functions. It turns out that the low-temperature behavior of correlation length of the chirality-pair correlation function is different from the one for the Ising model of spin ±1 but akin to the one for the Ising model of infinite spin. 相似文献
7.
Suchada Suntornchashwej Dr. Khanit Suwanborirux Dr. Kazushi Koga Minoru Isobe Prof. Dr. 《化学:亚洲杂志》2007,2(1):114-122
Malyngamide X ( 1 ), the first (7R)‐lyngbic acid connected to a new tripeptide backbone, was isolated from the Thai sea hare Bursatella leachii. The gross structure of 1 was established on the basis of 1D and 2D NMR and mass spectroscopic data. Combination of the NMR spectroscopic experiments with α‐methoxy‐α‐(trifluoromethyl)phenylacetic acid esters, 2,2,2‐trifluoro‐1‐(9‐anthryl)ethanol chiral solvating agent, and molecular mechanics of 1 and the synthetic molecular fragments allowed us to determine the absolute stereochemistry of all six stereogenic centers without hydrolytic degradation of the compound. Compound 1 displayed moderate cytotoxic, antitubercular, and antimalarial properties. 相似文献
8.
9.
Simulation of electron bunch generation by an ultrashort-pulse high-intensity laser-driven wakefield
M. Yamagiwa S. V. Bulanov T. Zh. Esirkepov J. Koga M. Kando Y. Ueshima K. Saito D. Wakabayashi 《Laser Physics》2006,16(2):252-258
Electron acceleration due to a wakefield excited by a ultrashort-pulse intense laser propagating through a finite-length underdense plasma layer is studied by two-dimensional particle-in-cell simulation. The electron energy distribution is analyzed for moderate to high intensity. For the electron density, where the pulse length is almost half of the plasma wavelength, dramatic changes of the density structure occur with cavity and bunch formation with an increase in the laser intensity, also leading to the appearance of a fast electron component well confined in phase space. The analytical form of the fast electron energy spectrum is also presented. 相似文献
10.