全文获取类型
收费全文 | 166137篇 |
免费 | 24670篇 |
国内免费 | 17526篇 |
专业分类
化学 | 111820篇 |
晶体学 | 1741篇 |
力学 | 10354篇 |
综合类 | 1161篇 |
数学 | 21207篇 |
物理学 | 62050篇 |
出版年
2024年 | 509篇 |
2023年 | 3031篇 |
2022年 | 5366篇 |
2021年 | 5717篇 |
2020年 | 6115篇 |
2019年 | 5831篇 |
2018年 | 5493篇 |
2017年 | 4960篇 |
2016年 | 7472篇 |
2015年 | 7450篇 |
2014年 | 9101篇 |
2013年 | 11943篇 |
2012年 | 14302篇 |
2011年 | 14732篇 |
2010年 | 10223篇 |
2009年 | 9888篇 |
2008年 | 10424篇 |
2007年 | 9366篇 |
2006年 | 8811篇 |
2005年 | 7428篇 |
2004年 | 5900篇 |
2003年 | 4678篇 |
2002年 | 4238篇 |
2001年 | 3631篇 |
2000年 | 3278篇 |
1999年 | 3545篇 |
1998年 | 3025篇 |
1997年 | 2661篇 |
1996年 | 2726篇 |
1995年 | 2413篇 |
1994年 | 2210篇 |
1993年 | 1834篇 |
1992年 | 1655篇 |
1991年 | 1438篇 |
1990年 | 1172篇 |
1989年 | 972篇 |
1988年 | 741篇 |
1987年 | 690篇 |
1986年 | 623篇 |
1985年 | 557篇 |
1984年 | 395篇 |
1983年 | 333篇 |
1982年 | 266篇 |
1981年 | 198篇 |
1980年 | 145篇 |
1979年 | 77篇 |
1978年 | 82篇 |
1976年 | 81篇 |
1975年 | 88篇 |
1973年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
201.
湿度对绝缘体表面电导和气体电导有一定的影响,但通常在湿度传感器的研究中忽略了气体电导的贡献。本文通过特殊设计装置来区分表面电导和气体电导,并分别从实验和理论上进行了定性的研究。 相似文献
202.
The main aim of this paper is to provide convergence analysis of Quasi-Wilson nonconforming finite element to Maxwell's equations under arbitrary quadrilateral meshes.The error estimates are derived,which are the same as those for conforming elements under conventional regular meshes. 相似文献
203.
A novel heath monitoring system of the rocket based on fiber optic Bragg gratings is brought forward, its component units and working principle are also described. 相似文献
204.
For the linear deterministic system with unknown orders and coefficients adaptive controls are given so that the closed-loop system is stabilized and the unknown parameters are consistently estimated. Moreover, if the parameter estimation is ignored, then the system input and output can be reduced to zero with an exponential rate.This project is supported by the National Natural Science Foundation of China.In Commemoration of the 15th Anniversary of the Acta Mathematicae Applicatae Sinica. 相似文献
205.
Controllability of Functional Integro-Differential Inclusions with an Unbounded Delay 总被引:1,自引:0,他引:1
In this paper, a sufficient condition is established for the controllability of neutral functional integro-differential inclusions
with an unbounded delay in Banach spaces. The approach used is a fixed-point theorem for condensing maps due to Martelli and
the theory of analytic semigroup of linear operators.
Communicated by F. Zirilli
Research supported by NNSF of China, by the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education
Institutions of the Ministry of Education of China, and by the Qing Lan Talent Engineering Fund QL-05-164 of Lanzhou Jiaotong
University. The authors are grateful to Professor F. Zirilli and two anonymous referees for valuable suggestions improving
this paper. 相似文献
206.
Gu-Qiang Li 《Theoretical and Mathematical Physics》2007,151(1):586-589
We use the Parikh-Wilczek method to treat Hawking radiation as a tunneling process across the event horizon and calculate
the emission rate of a Gibbons-Maeda dilaton black hole. We show that if self-gravitation is taken into account, then the
radiation deviates from the purely thermal spectrum, and the corrected spectrum is consistent with an underlying unitary theory.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 1, pp. 172–175, April, 2007. 相似文献
207.
B. Sun Yu. A. Litvinov P. M. Walker K. Beckert P. Beller F. Bosch D. Boutin C. Brandau L. Chen C. Dimopoulou H. Geissel R. Knöbel C. Kozhuharov J. Kurcewicz S. A. Litvinov M. Mazzocco J. Meng C. Nociforo F. Nolden W. R. Plass C. Scheidenberger M. Steck H. Weick M. Winkler 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):393-394
A new long-lived isomeric state in the near proton dripline nucleus 125Ce has been identified with Schottky mass spectrometry at GSI. The excitation energy E
* = 103(12)keV and the decay time of 193(1)s have been obtained from a single stored fully ionized 125m
Ce58+ ion. The data implies an E3 transition and a 1/2+ assignment for the spin of the isomer. 相似文献
208.
In solid immersion lens (SIL) microscopy systems with high numerical aperture (NA), there always exists the aberration produced by Fresnel effects at the interface between SIL and the sample. This aberration may cause the degradation of the image of sample. We design a continuous phase filter and optimize the optical field distribution of SIL system. The numerical results show that when the continuous phase filter is used, the field distribution of SIL system can be optimized, and the focal depth and intensity of transmitted light can be increased. At the same time, the intensity of side-lobe and the resolution are kept almost unchanged. 相似文献
209.
210.
在本文中引入了泛代数的二次扩张的概念,解决了TU-EC(A)和UT-EC(A)的存在、真类和基数问题,范畴TU-EC(A)(及UT-EC(A)),并得到了有关二次扩张的几个同构定理,还对一点二次扩张作了讨论。 相似文献