全文获取类型
收费全文 | 26789篇 |
免费 | 4832篇 |
国内免费 | 4468篇 |
专业分类
化学 | 20462篇 |
晶体学 | 413篇 |
力学 | 1491篇 |
综合类 | 350篇 |
数学 | 3213篇 |
物理学 | 10160篇 |
出版年
2024年 | 57篇 |
2023年 | 524篇 |
2022年 | 897篇 |
2021年 | 1070篇 |
2020年 | 1160篇 |
2019年 | 1252篇 |
2018年 | 976篇 |
2017年 | 1014篇 |
2016年 | 1345篇 |
2015年 | 1421篇 |
2014年 | 1717篇 |
2013年 | 2127篇 |
2012年 | 2495篇 |
2011年 | 2533篇 |
2010年 | 1893篇 |
2009年 | 1883篇 |
2008年 | 1993篇 |
2007年 | 1693篇 |
2006年 | 1582篇 |
2005年 | 1285篇 |
2004年 | 1029篇 |
2003年 | 813篇 |
2002年 | 855篇 |
2001年 | 680篇 |
2000年 | 542篇 |
1999年 | 519篇 |
1998年 | 428篇 |
1997年 | 348篇 |
1996年 | 307篇 |
1995年 | 267篇 |
1994年 | 222篇 |
1993年 | 215篇 |
1992年 | 151篇 |
1991年 | 145篇 |
1990年 | 125篇 |
1989年 | 115篇 |
1988年 | 89篇 |
1987年 | 52篇 |
1986年 | 56篇 |
1985年 | 59篇 |
1984年 | 31篇 |
1983年 | 24篇 |
1982年 | 27篇 |
1981年 | 13篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1972年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
Chun Yuan Deng 《Journal of Mathematical Analysis and Applications》2007,335(1):64-71
In this note, the Drazin inverses of products and differences of orthogonal projections on a Hilbert space are established. 相似文献
152.
153.
Crosslinking behaviors of acrylonitrile butadiene rubber (NBR)/poly (vinyl chloride) (PVC) alloy, filled with anhydrous copper sulfate (CuSO4) particles, were investigated for the first time by dynamic mechanical analysis (DMA) under hetero and isothermal modes, respectively. In the heterothermal testing, (NBR/PVC)/CuSO4 compound showed two marked increases in the storage modulus (E′), corresponding to coordination crosslinking of NBR-CuSO4 and self-crosslinking of NBR and PVC respectively. During the isothermal testing, a dramatic increase in E′ was found at the initial stage while that of original NBR/PVC alloy was not detected. The marked increase in E′ of (NBR/PVC)/CuSO4 compound was mainly due to the crosslinking induced by coordination between CN and Cu2+. The increasing extent of E′ increased with the rise of CuSO4 content, suggesting the formation of a greater number of crosslinks. Moreover, the activation energy (Ea) of crosslinking process was about 139 kJ/mol. In this work, fourier transform infrared spectrum (FT-IR) and equilibrium swelling method were also performed for the characterization of the compound. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 41–51, 2007 相似文献
154.
ZHANG Lin-bo LIU Xiao-hua ** JIANG Yuan GUO Ping SHA Li-jin LI Yu . Institute of Mycology . College of Biotechnology Jilin Agricultural University Changchun P.R. China 《高等学校化学研究》2006,(2)
Introduction Parkinson′sdisease(PD),alsocalledshaking palsy,isaneurodegenerativedisorderandfrequently occursinthepeopleabovetheageof65[1].PDisa relativelycommonneurodegenerativedisorder,which hasclinicalsymptomsincludingbradykinesia,rest tremor,rigidity,… 相似文献
155.
In this paper we investigate the acute triangulations of flat Mobius strips. We find out that we can always triangulate a
flat Mobius strip with at most nine acute triangles, and sometimes (but not always) that many triangles are really needed. 相似文献
156.
The fission barrier for ^240pu is investigated beyond the second saddle point in the potentiM energy surface by the constrained relativistic mean field method with the newly proposed parameter set PK1. The microscopic correction for the centre-of-mass motion is essentiM to provide the correct potential energy surface. The shell effects that stabilize the nuclei against the fission is also investigated by the Strutinsky method. The shapes for the ground state, fission isomer and saddle-points, etc, are studied in detail. 相似文献
157.
In this note we study constant mean curvature surfaces in asymptotically flat 3-manifolds. We prove that, outside a given compact subset in an asymptotically flat 3-manifold with positive mass, stable spheres of given constant mean curvature are unique. Therefore we are able to conclude that the foliation of stable spheres of constant mean curvature in an asymptotically flat 3-manifold with positive mass outside a given compact subset is unique.
158.
根据由赝势法得到的非理想玻色气体的自由能和状态方程,研究了相互作用对凝聚温度的影响.从热力学角度揭示了存在引力作用时定压热容量、等温压缩系数、定压膨胀系数的反常热力学特性.研究了引力作用下玻色气体系统的不稳定性,给出了不稳定性的温度判据和粒子数密度判据.
关键词:
相互作用
玻色气体
热力学性质
不稳定性判据 相似文献
159.
160.
Wei Gang SU Huai Jie ZHONG 《数学学报(英文版)》2006,22(2):515-522
This paper introduces the concept of the generalized Riesz operators and the concept of the generalized West decomposition of a general operator which generalizes the definition of the West decomposition of Riesz operators, and proves that the following three statements are equivalent on a general Banach space:
(a) Every generalized Riesz operator has the generalized West decomposition;
(b) Every operator makes strong Stampfli theorem true; Every operator has Apostol's compact correction. 相似文献