全文获取类型
收费全文 | 1240篇 |
免费 | 169篇 |
国内免费 | 136篇 |
专业分类
化学 | 874篇 |
晶体学 | 10篇 |
力学 | 77篇 |
综合类 | 9篇 |
数学 | 157篇 |
物理学 | 418篇 |
出版年
2024年 | 6篇 |
2023年 | 35篇 |
2022年 | 58篇 |
2021年 | 62篇 |
2020年 | 72篇 |
2019年 | 56篇 |
2018年 | 51篇 |
2017年 | 55篇 |
2016年 | 59篇 |
2015年 | 50篇 |
2014年 | 77篇 |
2013年 | 96篇 |
2012年 | 114篇 |
2011年 | 103篇 |
2010年 | 67篇 |
2009年 | 55篇 |
2008年 | 62篇 |
2007年 | 69篇 |
2006年 | 64篇 |
2005年 | 52篇 |
2004年 | 25篇 |
2003年 | 30篇 |
2002年 | 22篇 |
2001年 | 26篇 |
2000年 | 26篇 |
1999年 | 21篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 21篇 |
1995年 | 10篇 |
1994年 | 16篇 |
1993年 | 7篇 |
1992年 | 17篇 |
1991年 | 10篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1970年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有1545条查询结果,搜索用时 15 毫秒
961.
Xing-Wu Liu Chun-Fang Huo Yong-Wang Li Jianguo Wang Haijun Jiao 《Surface science》2012,606(7-8):733-739
Spin-polarized density functional theory calculations have been performed to investigate carbon deposition and carbide formation on Fe(100) and Fe(110) at different carbon coverage. On Fe(100) with increasing carbon coverage, the most stable carbon adsorption configuration changes from surface carbon adsorption to surface carbon diffusion into subsurface, and surface carbon clustering is not favored thermodynamically. However, surface carbon clustering is more favored kinetically than carbon diffusion; and carbon diffusion into subsurface and surface carbon clustering become competitive. On Fe(110) with increasing surface carbon coverage, the most stable adsorption configuration changes from surface carbon adsorption to surface carbon diffusion into subsurface, and this process is favored both kinetically and thermodynamically, and surface carbon clustering is neither favored nor competitive. Surface carbon deposition might form on Fe(100), while carbide formation might be found on Fe(110). 相似文献
962.
963.
964.
965.
966.
967.
Huo Bianbian Chen Mingli Chen Junjie Li Yuanyuan Zhang Wanjun Wang Jianhua Qin Weijie Qian Xiaohong 《Analytical and bioanalytical chemistry》2018,410(28):7305-7312
Analytical and Bioanalytical Chemistry - Urine is an attractive and non-invasive alternative source to tissue, blood or other biofluids for biomarker screening in clinical research. In normal human... 相似文献
968.
The moment of inertia of the proto neutron star PSR J0348+0432 is studied in the framework of relativistic mean field theory under neutrino trapped. We find that the temperature of the PNS PSR J0348+0432 increases with the increase of the baryon number density and at the center of the star it is in the range Tc = 41.662–45.685 MeV. Corresponding to the observation mass 1.97–2.05 M⊙, the radius of the NS PSR J0348+0432 is in the range 12.948–12.16 km whereas that of the PNS PSR J0348+0432 is in the range 14.46–13.561 km. The radius of the PNS PSR J0348+0432 has increased by 11.7%–11.5% compared with that of the NS PSR J0348+0432. The central moment of inertia of the PNS PSR J0348+0432 is in the range 2.207?×?1045–1.914?×?1045 g cm2 whereas that of the NS PSR J0348+0432 is only in the range 1.9?×?1045–1.552?×?1045 g cm2. Compared with the moment of inertia of the NS PSR J0348+0432, the central moment of inertia of the PNS PSR J0348+0432 increases by 16%–23%. 相似文献
969.
Metabolic profiling of luteolin‐7‐O‐glucoside in rat urine,plasma, bile and feces after oral administration using ultra‐high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry
下载免费PDF全文
![点击此处可从《Rapid communications in mass spectrometry : RCM》网站下载免费的PDF全文](/ch/ext_images/free.gif)
970.
Finite-difference time-domain (FDTD) method is used to perform three dimension simulations for the optical performance of 1.75 μm pitch pixels of CMOS image sensor. A three dimension pixel model for CMOS image sensor pixels is set up. Micro-lens optimization, dielectric stack height reduction can decrease the optical power loss. A SiN layer with proper thickness can reduce the reflection at the Si–SiO2 interface. A high refractive index lightpipe is proposed to confine the light within the pixel. The simulation results show that the optical efficiency of the optimized 1.75 μm pixel compare to that before optimized is promoted by more than 10% and the cross-talk is reduced by 50%. 相似文献