全文获取类型
收费全文 | 5164篇 |
免费 | 764篇 |
国内免费 | 725篇 |
专业分类
化学 | 3880篇 |
晶体学 | 57篇 |
力学 | 315篇 |
综合类 | 68篇 |
数学 | 618篇 |
物理学 | 1715篇 |
出版年
2024年 | 8篇 |
2023年 | 83篇 |
2022年 | 106篇 |
2021年 | 132篇 |
2020年 | 199篇 |
2019年 | 172篇 |
2018年 | 180篇 |
2017年 | 168篇 |
2016年 | 219篇 |
2015年 | 229篇 |
2014年 | 278篇 |
2013年 | 362篇 |
2012年 | 400篇 |
2011年 | 481篇 |
2010年 | 332篇 |
2009年 | 315篇 |
2008年 | 357篇 |
2007年 | 326篇 |
2006年 | 274篇 |
2005年 | 221篇 |
2004年 | 203篇 |
2003年 | 168篇 |
2002年 | 185篇 |
2001年 | 145篇 |
2000年 | 118篇 |
1999年 | 126篇 |
1998年 | 99篇 |
1997年 | 76篇 |
1996年 | 77篇 |
1995年 | 70篇 |
1994年 | 75篇 |
1993年 | 69篇 |
1992年 | 59篇 |
1991年 | 52篇 |
1990年 | 51篇 |
1989年 | 39篇 |
1988年 | 29篇 |
1987年 | 35篇 |
1986年 | 28篇 |
1985年 | 21篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 19篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1957年 | 4篇 |
排序方式: 共有6653条查询结果,搜索用时 453 毫秒
1.
Tian Xiu-Zhi Yang Rui Ma Jia-Jia Ni Yong-Hao Deng Hai-Bo Dai Lei Tan Jiao-Jun Zhang Mei-Yun Jiang Xue 《高分子科学》2022,40(7):789-798
Chinese Journal of Polymer Science - Antistatic and strength properties are of vital importance for polyurethane rubber used in moving parts of many industrial instruments. Herein, polyurethane was... 相似文献
2.
Low-flow chromatography has a rich history of innovation but has yet to reach widespread implementation in bioanalytical applications. Improvements in pump technology, microfluidic connections, and nano-electrospray sources for MS have laid the groundwork for broader application, and innovation in this space has accelerated in recent years. This article reviews the instrumentation used for nano-flow LC, the types of columns employed, and strategies for multidimensionality of separations, which are key to the future state of the technique to the high-throughput needs of modern bioanalysis. An update of the current applications where nano-LC is widely used, such as proteomics and metabolomics, is discussed. But the trend toward biopharmaceutical development of increasingly complex, targeted, and potent therapeutics for the safe treatment of disease drives the need for ultimate selectivity and sensitivity of our analytical platforms for targeted quantitation in a regulated space. The selectivity needs are best addressed by mass spectrometric detection, especially at high resolutions, and exquisite sensitivity is provided by nano-electrospray ionization as the technology continues to evolve into an accessible, robust, and easy-to-use platform. 相似文献
3.
Analysis and pharmacokinetic study of polyphyllin H in beagle dog plasma after oral administration of Rhizoma Paridis Extracts by LC‐MS/MS 下载免费PDF全文
4.
Yi Han Zibo Xue Dr. Guangwu Li Dr. Yanwei Gu Dr. Yong Ni Dr. Shaoqiang Dong Prof. Chunyan Chi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):9111-9116
Incorporation of a non-hexagonal ring into a nanographene framework can lead to new electronic properties. During the attempted synthesis of naphthalene-bridged double [6]helicene and heptagon-containing nanographene by the Scholl reaction, an unexpected azulene-embedded nanographene and its triflyloxylated product were obtained, as confirmed by X-ray crystallographic analysis and 2D NMR spectroscopy. A 5/7/7/5 ring-fused substructure containing two formal azulene units is formed, but only one of them shows an azulene-like electronic structure. The formation of this unique structure is explained by arenium ion mediated 1,2-phenyl migration and a naphthalene to azulene rearrangement reaction according to an in-silico study. This report represents the first experimental example of the thermodynamically unfavorable naphthalene to azulene rearrangement and may lead to new azulene-based molecular materials. 相似文献
5.
The complex-scaled Green's function(CGF)method is employed to explore the single-proton resonance in 15F.Special attention is paid to the first excited resonant state 5/2+,which has been widely studied in both theory and experiments.However,past studies generally overestimated the width of the 5/2+state.The predicted energy and width of the first excited resonant state 5/2+by the CGF method are both in good agreement with the experimental value and close to Fortune's new estimation.Furthermore,the influence of the potential parameters and quadruple deformation effects on the resonant states are investigated in detail,which is helpful to the study of the shell structure evolution. 相似文献
6.
Dr. Wan‐Ling Liu Ni‐Shin Yang Ya‐Ting Chen Stephen Lirio Cheng‐You Wu Prof. Chia‐Her Lin Prof. Hsi‐Ya Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):115-119
A green and sustainable strategy synthesizes clinical medicine warfarin anticoagulant by using lipase‐supported metal–organic framework (MOF) bioreactors (see scheme). These findings may be beneficial for future studies in the industrial production of chemical, pharmaceutical, and agrochemical precursors. 相似文献
7.
Prof. Jen-Shyang Ni Tianliang Min Yaxi Li Menglei Zha Dr. Pengfei Zhang Prof. Chun Loong Ho Prof. Kai Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10265-10271
Planar luminogens have encountered difficulties in overcoming intrinsic aggregation-caused emission quenching by intermolecular π-π stacking interactions. Although excited-state double-bond reorganization (ESDBR) can guide us on designing planar aggregation-induced emission (AIE) luminogens (AIEgens), its mechanism has yet been elucidated. Major challenges in the field include methods to efficiently restrict ESDBR and enhance AIE performance without using bulky substituents (e.g., tetraphenylethylene and triphenylamine). In this study, we rationally developed fluoro-substituent AIEgens with stronger intermolecular H-bonding interaction for restricted molecular motions and increased crystal density, leading to decreased nonradiative decay rate by one order of magnitude. The adjusted ESDBR properties also show a corresponding response to variation in viscosity. Furthermore, their aggregation-induced reactive oxygen species (ROS) generations have been discovered. The application of such planar AIEgen in treating multidrug-resistant bacteria has been demonstrated in a mouse model. The relationship between ROS generation and distinct E/Z-configurational stacking behaviors have been further understood, providing a design principle for synthesizing planar AIEgen-based photosensitizers. 相似文献
8.
We initiate a program to study certain recent problems in non-compact coset CFT by the BRST approach. We derive a reduction formula for the BRST cohomology by making use of a twisting by highest weight modules. As illustrations, we apply the formula to the bosonic string model and a rank one non-compact coset model [DPL]. Our formula provides a completely new approach to non-compact coset construction.Partially supported by NSF Grant DMS-8703581 相似文献
9.
10.
YBa2Cu3O7-x (YBCO) bulk is one of the most important high temperature superconducting materials for magnetic levitation applications, because it has a high magnetic irreversibility field Hirr at liquid nitrogen temperature, and can grow into large grains. The levitation force of YBCO bulk is proportional to the critical current density (Jc) and grain radius (r)[1], so higher Jc and r are appreciated for YBCO bulks to achieve higher levitation force. Now single-domain YBCO bulks up to s… 相似文献