全文获取类型
收费全文 | 2037篇 |
免费 | 89篇 |
国内免费 | 15篇 |
专业分类
化学 | 1568篇 |
晶体学 | 12篇 |
力学 | 32篇 |
综合类 | 16篇 |
数学 | 220篇 |
物理学 | 293篇 |
出版年
2023年 | 18篇 |
2022年 | 14篇 |
2021年 | 38篇 |
2020年 | 43篇 |
2019年 | 52篇 |
2018年 | 36篇 |
2017年 | 25篇 |
2016年 | 54篇 |
2015年 | 50篇 |
2014年 | 54篇 |
2013年 | 113篇 |
2012年 | 146篇 |
2011年 | 145篇 |
2010年 | 74篇 |
2009年 | 91篇 |
2008年 | 155篇 |
2007年 | 132篇 |
2006年 | 125篇 |
2005年 | 132篇 |
2004年 | 112篇 |
2003年 | 82篇 |
2002年 | 91篇 |
2001年 | 22篇 |
2000年 | 28篇 |
1999年 | 21篇 |
1998年 | 23篇 |
1997年 | 21篇 |
1996年 | 22篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 17篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 4篇 |
1985年 | 18篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 5篇 |
排序方式: 共有2141条查询结果,搜索用时 0 毫秒
991.
Geometric Formulation and Multi‐dark Soliton Solution to the Defocusing Complex Short Pulse Equation 下载免费PDF全文
In the present paper, we study the defocusing complex short pulse (CSP) equations both geometrically and algebraically. From the geometric point of view, we establish a link of the complex coupled dispersionless (CCD) system with the motion of space curves in Minkowski space , then with the defocusing CSP equation via a hodograph (reciprocal) transformation, the Lax pair is constructed naturally for the defocusing CSP equation. We also show that the CCD system of both the focusing and defocusing types can be derived from the fundamental forms of surfaces such that their curve flows are formulated. In the second part of the paper, we derive the defocusing CSP equation from the single‐component extended Kadomtsev‐Petviashvili (KP) hierarchy by the reduction method. As a by‐product, the N‐dark soliton solution for the defocusing CSP equation in the form of determinants for these equations is provided. 相似文献
992.
Hiroaki Kobayashi Yôtarô Nishio Ken Kanazawa Shinji Kuroda Masanori Mitome Yoshio Bando 《Physica B: Condensed Matter》2012,407(15):2947-2949
We have studied the structural properties of the phase separation in Zn1−xCrxTe films grown by MBE with a relatively high Cr composition x∼0.2. In the combined analyses using TEM and EELS, it has been revealed that the Cr-aggregated regions are composed of precipitates of the hexagonal structure, which are formed in a particular crystallographic relation with the zinc-blende (ZB) structure of the matrix that the c-plane of the hexagonal structure nearly parallel to the (1 1 1) plane of the ZB structure. In the XRD measurements, the diffraction from the hexagonal precipitates has been detected in the ω-scan. From the measurements on the series of films grown at different temperatures, it has been suggested the hexagonal precipitates were formed in a larger quantity with the increase in growth temperature. 相似文献
993.
Observation of temporal vector soliton propagation and collision in birefringent fiber 总被引:1,自引:0,他引:1
Rand D Glesk I Brès CS Nolan DA Chen X Koh J Fleischer JW Steiglitz K Prucnal PR 《Physical review letters》2007,98(5):053902
We report the experimental observation of temporal vector soliton propagation and collision in a linearly birefringent optical fiber. To the best of the authors' knowledge, this is both the first demonstration of temporal vector solitons with two mutually incoherent component fields, and of vector soliton collisions in a Kerr nonlinear medium. Collisions are characterized by an intensity redistribution between the two components, and the experimental results agree with numerical predictions of the coupled nonlinear Schr?dinger equation. 相似文献
994.
995.
996.
Ken‐ichi Nakashima Naohito Abe Fumiko Kamiya Tetsuro Ito Masayoshi Oyama Munekazu Iinuma 《Helvetica chimica acta》2009,92(10):1999-2008
The three novel methylene bis[flavonoids] 1 – 3 , the novel 2‐flavene 4 , the new naturally occurring flavan 5 , and the new retro‐dihydrochalcone 6 were isolated from dragon's blood of Daemonorops draco, together with seven known compounds. The structures were elucidated by extensive 1D‐ and 2D‐NMR spectroscopic analysis. 相似文献
997.
Shigeru Furuichi Ken Kuriyama Kenjiro Yanagi 《Linear algebra and its applications》2009,430(8-9):2271-2276
In this short paper, we study some trace inequalities of the products of the matrices and the power of matrices by the use of elementary calculations. 相似文献
998.
Ken Hatano Tetsuya Yamazaki Koji Yoshino Naoto Ohyama Tetsuo Koyama Koji Matsuoka Daiyo Terunuma 《Tetrahedron letters》2008,49(39):5593-5596
A novel O-protected lactose (Galβ1→4Glcβ1-) derivative bearing trimethoxysilyl group at the aglycon was developed as a silane coupling agent. Reaction of the coupling agent with tris(2,2′-bipyridine)ruthenium (II) dichloride (Rubpy) doped silica particle gave a Rubpy-doped silica particle peripherally functionalized with O-protected lactose derivative. De-O-protection of the particle with aqueous ammonia provided lactose-coating Rubpy-doped silica particles, combining luminophor encapsulated in silica matrix and carbohydrate having lectin-recognition ability. Specific adhesion of fluorescein isothiocyanate-labeled peanut agglutinin (FITC-PNA) to the lactose-coating Rubpy-doped silica particles was confirmed by fluorescence microscopic analysis. 相似文献
999.
Asymptotic analysis on some statistical properties of the random binary-tree model is developed. We quantify a hierarchical
structure of branching patterns based on the Horton-Strahler analysis. We introduce a transformation of a binary tree, and
derive a recursive equation about branch orders. As an application of the analysis, topological self-similarity and its generalization
is proved in an asymptotic sense. Also, some important examples are presented. 相似文献
1000.