全文获取类型
收费全文 | 17063篇 |
免费 | 2189篇 |
国内免费 | 2004篇 |
专业分类
化学 | 13415篇 |
晶体学 | 187篇 |
力学 | 662篇 |
综合类 | 149篇 |
数学 | 2458篇 |
物理学 | 4385篇 |
出版年
2024年 | 25篇 |
2023年 | 249篇 |
2022年 | 326篇 |
2021年 | 576篇 |
2020年 | 682篇 |
2019年 | 701篇 |
2018年 | 550篇 |
2017年 | 527篇 |
2016年 | 851篇 |
2015年 | 827篇 |
2014年 | 939篇 |
2013年 | 1271篇 |
2012年 | 1585篇 |
2011年 | 1628篇 |
2010年 | 1100篇 |
2009年 | 1015篇 |
2008年 | 1208篇 |
2007年 | 1100篇 |
2006年 | 1006篇 |
2005年 | 857篇 |
2004年 | 746篇 |
2003年 | 544篇 |
2002年 | 576篇 |
2001年 | 394篇 |
2000年 | 274篇 |
1999年 | 265篇 |
1998年 | 194篇 |
1997年 | 141篇 |
1996年 | 136篇 |
1995年 | 107篇 |
1994年 | 102篇 |
1993年 | 90篇 |
1992年 | 112篇 |
1991年 | 76篇 |
1990年 | 84篇 |
1989年 | 52篇 |
1988年 | 40篇 |
1987年 | 46篇 |
1986年 | 38篇 |
1985年 | 39篇 |
1984年 | 28篇 |
1983年 | 24篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1959年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
1.
Dan Chen Kaixin Du Xiaochen Niu Hongwei Zhang Xue Zhang Yu Tang Jianchun Zhao 《Biomedical chromatography : BMC》2022,36(3):e5288
Amlexanox, an anti-inflammatory and anti-allergic agent, has been widely used clinically for the treatment of canker sores, asthma, and allergic rhinitis. Recently, amlexanox has received considerable attention in curing nonalcoholic fatty liver diseases and hepatitis virus infection. Herein, we first established a sensitive high-performance liquid chromatography-tandem mass spectrum (LC–MS/MS) method for the determination of amlexanox in rat plasma. Propranolol was used as the internal standard (IS). Using a simple protein precipitation method, the amlexanox and IS were separated with Capcell Pak C18 column (2.0 × 50 mm, 5 μm) and eluted with water and acetonitrile each containing 0.1% formic acid using gradient elution condition at a flow rate of 0.4 mL·min−1. Amlexanox and IS were detected by a triple quadrupole mass in multiple reactive monitoring (MRM) under the transitions of m/z 299.2 → 281.2 and m/z 259.9 → 116.1 with positive electrospray ionization, respectively. The calibration curves of amlexanox were established with the range of 50 to 2000 ng·mL−1 (r2 > 0.99). The validation method consisted of selectivity, accuracy, precision, carryover effect, matrix effect, recovery, dilution effect, and stability. The fully validated method was successfully applied to the pharmacokinetic study of amlexanox in Wistar rats. 相似文献
2.
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
3.
4.
Ruirui Xu Kun Wang Haoying Liu Prof. Dr. Weijun Tang Dr. Huaming Sun Prof. Dr. Dong Xue Prof. Dr. Jianliang Xiao Prof. Dr. Chao Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22143-22148
A ruthenium-catalyzed formal anti-Markovnikov hydroamination of allylic alcohols for the synthesis of chiral γ-amino alcohols is presented. Proceeding via an asymmetric hydrogen-borrowing process, the catalysis allows racemic secondary allylic alcohols to react with various amines, affording enantiomerically enriched chiral γ-amino alcohols with broad substrate scope and excellent enantioselectivities (68 examples, up to >99 % ee). 相似文献
5.
氧化铝晶体是一种优良的光学透明窗口材料,更是地球内部的重要组成物质.利用气炮加载结合冲击光谱测量,不仅能够获得其发光特征,并且根据光谱分布特征得到高压结构相变信息.在自主搭建的冲击光谱动态测试平台上,结合多通道辐射高温计以及ICCD瞬态光谱测试技术在40~120 GPa的压力区间,研究了c切向氧化铝晶体的辐射发光效应.在可见光波段400~700 nm区间获得了氧化铝晶体的发光光谱和辐射温度结果,证实了光谱的结构特征和表观温度值与该压力下氧化铝的结构相变存在明显的关联性. 相似文献
6.
We study the full counting statistics of transport electrons through a semiconductor two-level quantum dot with Rashba spin–orbit (SO) coupling, which acts as a nonabelian gauge field and thus induces the electron transition between two levels along with the spin flip. By means of the quantum master equation approach, shot noise and skewness are obtained at finite temperature with two-body Coulomb interaction. We particularly demonstrate the crucial effect of SO coupling on the super-Poissonian fluctuation of transport electrons, in terms of which the SO coupling can be probed by the zero-frequency cumulants. While the charge currents are not sensitive to the SO coupling. 相似文献
7.
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
8.
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
9.
We present the fabrication of core-shell-satellite Au@SiO2-Pt nanostructures and demonstrate that LSPR excitation of the core Au nanoparticle can induce plasmon coupling effect to initiate photocatalytic hydrogen generation from decomposition of formic acid. Further studies suggest that the plasmon coupling effect induces a strong local electric field between the Au core and Pt nanoparticles on the SiO2 shell, which enables creation of hot electrons on the non-plasmonic-active Pt nanoparticles to participate hydrogen evolution reaction on the Pt surface. In addition, small SiO2 shell thickness is required in order to obtain a strong plamon coupling effect and achieve efficient photocatalytic activities for hydrogen generation. 相似文献
10.