全文获取类型
收费全文 | 2688篇 |
免费 | 688篇 |
国内免费 | 1091篇 |
专业分类
化学 | 1959篇 |
晶体学 | 129篇 |
力学 | 151篇 |
综合类 | 94篇 |
数学 | 480篇 |
物理学 | 1654篇 |
出版年
2024年 | 12篇 |
2023年 | 33篇 |
2022年 | 102篇 |
2021年 | 108篇 |
2020年 | 98篇 |
2019年 | 108篇 |
2018年 | 95篇 |
2017年 | 148篇 |
2016年 | 78篇 |
2015年 | 153篇 |
2014年 | 161篇 |
2013年 | 213篇 |
2012年 | 203篇 |
2011年 | 244篇 |
2010年 | 219篇 |
2009年 | 263篇 |
2008年 | 312篇 |
2007年 | 294篇 |
2006年 | 260篇 |
2005年 | 214篇 |
2004年 | 147篇 |
2003年 | 112篇 |
2002年 | 131篇 |
2001年 | 128篇 |
2000年 | 165篇 |
1999年 | 81篇 |
1998年 | 60篇 |
1997年 | 37篇 |
1996年 | 26篇 |
1995年 | 35篇 |
1994年 | 33篇 |
1993年 | 28篇 |
1992年 | 24篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 20篇 |
1988年 | 14篇 |
1987年 | 13篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有4467条查询结果,搜索用时 0 毫秒
101.
Dressed Four-Wave Mixing Spectroscopy Modified by Polarization Interference and Atom-Wall Collision in Micrometric Thin Cells 下载免费PDF全文
Dressed four-wave mixing (DFWM) spectroscopy is investigated theoretically in some micrometric thin cells. It is found that DFWM spectra can be modified by polarization interference of atoms and transient effects induced by atom-wall collision. This modification can lead to width-narrowing of DFWM lines and facilitates to implement experiment of high resolution DFWM spectroscopy in a confined atomic system. 相似文献
102.
Investigation on Guided-Mode Characteristics of Hollow-Core Photonic Crystal Fibre at Near-Infrared Wavelengths 下载免费PDF全文
Guided-mode characteristics of hollow-core photonic crystal fibre (HC-PCF) are experimentally and theoretically investigated. The transmission spectrum in the range from 755 to 845nm is observed and the loss is measured to be 0.12dB/m at 800nm by cut-back method. Based on the full-vector beam propagation method and the full-vector plane-wave method, the characteristics of mode field over propagation distance 1 m are simulated, and the results show that the propagation efficiency can be above 80%. Compared with the fundamental guided mode well confined in air core within shorter propagation distance, the second-order guided mode leaks into the cladding region and gradually attenuates due to larger refractive index difference. The primary loss factors in HC-PCF and the corresponding solutions are elementarily discussed. 相似文献
103.
104.
Details of the active ways to suppress Closed Orbit Distortion (COD), including bending magnet sorting and survey and alignment of the magnets, are discussed based on the studies of affections to the COD by the bending magnet field error and the misalignment of quadrupoles. The closed orbit correction and the Slow Orbit Feed Back (SOFB) system for the SSRF storage ring are presented in this paper. With these available methods, better results were obtained during the commissioning period with 3 GeV beam energy. 相似文献
105.
106.
Research and development of a 1.3 GHz 9-cell cavity test cryomodule were carried out by a collaboration group between IHEP (Institute of High Energy Physics) and TIPC (Technical Institute of Physics and Chemistry) in China. The cryomodule is a "test model" for the ILC cryomodule, and a key component of a superconducting accelerator test unit which will be built in the near future, also can be used as a horizontal test facility for 1.3~GHz 9-cell cavities. This paper presents the development status of the cryomodule, including structure design, cryogenic flow diagram, thermal and mechanical simulations, heat load estimation and etc. 相似文献
107.
108.
109.
110.
用荧光光谱和紫外.可见吸收光谱法研究了在不同温度下,新合成的过硒二苯2,2’-二甲酸(PSD)对牛血清白蛋白(BSA)作用的荧光猝灭光谱行为。分别用Stem-Volmer方程和Lineweaver-Burk双倒数方程处理试验数据,证实在试验浓度和温度范围内,其荧光猝灭作用更符合静态猝灭作用特征,PSD与BSA可反应并结合形成具有一定结构的复合物,得到了反应的结合常量、结合热力学性质和结合位点等参数;同时探讨了静态猝灭作用的机理和结合力的性质,为了解PSD与BSA的结合方式、在人体内的传输机理和药理作用提供科学依据。 相似文献