全文获取类型
收费全文 | 11417篇 |
免费 | 212篇 |
国内免费 | 45篇 |
专业分类
化学 | 6843篇 |
晶体学 | 79篇 |
力学 | 363篇 |
数学 | 1777篇 |
物理学 | 2612篇 |
出版年
2021年 | 170篇 |
2020年 | 157篇 |
2019年 | 150篇 |
2018年 | 148篇 |
2017年 | 126篇 |
2016年 | 201篇 |
2015年 | 197篇 |
2014年 | 205篇 |
2013年 | 669篇 |
2012年 | 430篇 |
2011年 | 527篇 |
2010年 | 381篇 |
2009年 | 325篇 |
2008年 | 487篇 |
2007年 | 446篇 |
2006年 | 439篇 |
2005年 | 389篇 |
2004年 | 396篇 |
2003年 | 332篇 |
2002年 | 324篇 |
2001年 | 200篇 |
2000年 | 198篇 |
1999年 | 162篇 |
1998年 | 129篇 |
1997年 | 142篇 |
1996年 | 157篇 |
1995年 | 134篇 |
1994年 | 129篇 |
1993年 | 158篇 |
1992年 | 162篇 |
1991年 | 170篇 |
1990年 | 120篇 |
1989年 | 126篇 |
1988年 | 133篇 |
1987年 | 187篇 |
1986年 | 148篇 |
1985年 | 207篇 |
1984年 | 194篇 |
1983年 | 148篇 |
1982年 | 173篇 |
1981年 | 184篇 |
1980年 | 180篇 |
1979年 | 183篇 |
1978年 | 172篇 |
1977年 | 166篇 |
1976年 | 145篇 |
1975年 | 163篇 |
1974年 | 133篇 |
1973年 | 126篇 |
1972年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
1.
JETP Letters - Extraordinary multiparticle effects in quantizing magnetic fields that are manifested in strongly interacting two-dimensional electron systems in MgZnO/ZnO heterostructures have been... 相似文献
2.
3.
Close‐Packed Two‐Dimensional Silver Nanoparticle Arrays: Quadrupolar and Dipolar Surface Plasmon Resonance Coupling 下载免费PDF全文
Sukang Yun Soonchang Hong Jesus A. I. Acapulco Jr. Ho Young Jang Songyi Ham Kyungeun Lee Prof. Seong Kyu Kim Prof. Sungho Park 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6165-6172
Silver nanoparticles (NPs) ranging in size from 40 to 100 nm were prepared in high yield by using an improved seed‐mediated method. The homogeneous Ag NPs were used as building blocks for 2D assembled Ag NP arrays by using an oil/water interface. A close‐packed 2D array of Ag NPs was fabricated by using packing molecules (3‐mercaptopropyltrimethoxysilane) to control the interparticle spacing. The homogeneous 2D Ag NP array exhibited a strong quadrupolar cooperative plasmon mode resonance and a dipolar red‐shift relative to individual Ag NPs suspended in solution. A well‐arranged 2D Ag NP array was embedded in polydimethylsiloxane film and, with biaxial stretching to control the interparticle distance, concomitant variations of the quadrupolar and dipolar couplings were observed. As the interparticle distance increased, the intensity of the quadrupolar cooperative plasmon mode resonance decreased and dipolar coupling completely disappeared. The local electric field of the 2D Ag NP array was calculated by using finite difference time domain simulation and qualitatively showed agreement with the experimental measurements. 相似文献
4.
5.
6.
7.
8.
Design and development of a two‐dimensional system based on hydrophilic and reversed‐phase liquid chromatography with on‐line sample treatment for the simultaneous separation of excreted xenobiotics and endogenous metabolites in urine 下载免费PDF全文
Diego García‐Gómez Encarnación Rodríguez‐Gonzalo Rita Carabias‐Martínez 《Biomedical chromatography : BMC》2015,29(8):1190-1196
In the present work we describe a two‐dimensional liquid chromatographic system (2D‐LC) with detection by mass spectrometry (MS) for the simultaneous separation of endogenous metabolites of clinical interest and excreted xenobiotics deriving from exposure to toxic compounds. The 2D‐LC system involves two orthogonal chromatographic modes, hydrophilic interaction liquid chromatography (HILIC) to separate polar endogenous metabolites and reversed‐phase (RP) chromatography to separate excreted xenobiotics of low and intermediate polarity. Additionally, the present proposal has the novelty of incorporating an on‐line sample treatment based on the use of restricted access materials (RAMs), which permits the direct injection of urine samples into the system. The work is focused on the instrumental coupling, studying all possible options and attempting to circumvent the problems of solvent incompatibility between the RAM device and the two chromatographic columns, HILIC and RP. The instrumental configuration developed, RAM‐HILIC‐RPLC‐MS/MS, allows the simultaneous assessment of urinary metabolites of clinical interest and excreted compounds derived from exposure to toxic agents with minimal sample manipulation. Thus, it may be of interest in areas such as occupational and environmental toxicology in order to explore the possible relationship between the two types of compounds. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
10.