全文获取类型
收费全文 | 39958篇 |
免费 | 5753篇 |
国内免费 | 3621篇 |
专业分类
化学 | 27544篇 |
晶体学 | 368篇 |
力学 | 2288篇 |
综合类 | 241篇 |
数学 | 5225篇 |
物理学 | 13666篇 |
出版年
2023年 | 767篇 |
2022年 | 739篇 |
2021年 | 1235篇 |
2020年 | 1522篇 |
2019年 | 1406篇 |
2018年 | 1214篇 |
2017年 | 1093篇 |
2016年 | 1722篇 |
2015年 | 1663篇 |
2014年 | 2074篇 |
2013年 | 2749篇 |
2012年 | 3464篇 |
2011年 | 3512篇 |
2010年 | 2370篇 |
2009年 | 2219篇 |
2008年 | 2483篇 |
2007年 | 2174篇 |
2006年 | 2066篇 |
2005年 | 1767篇 |
2004年 | 1514篇 |
2003年 | 1129篇 |
2002年 | 1040篇 |
2001年 | 744篇 |
2000年 | 682篇 |
1999年 | 815篇 |
1998年 | 706篇 |
1997年 | 642篇 |
1996年 | 743篇 |
1995年 | 631篇 |
1994年 | 579篇 |
1993年 | 496篇 |
1992年 | 472篇 |
1991年 | 389篇 |
1990年 | 336篇 |
1989年 | 250篇 |
1988年 | 232篇 |
1987年 | 219篇 |
1986年 | 158篇 |
1985年 | 176篇 |
1984年 | 162篇 |
1983年 | 126篇 |
1982年 | 113篇 |
1981年 | 87篇 |
1980年 | 61篇 |
1979年 | 52篇 |
1978年 | 57篇 |
1977年 | 38篇 |
1976年 | 51篇 |
1975年 | 40篇 |
1974年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Shang‐Xiong Huang‐Fu Jin‐Ni Shen Prof. Hua Lin Prof. Ling Chen Prof. Li‐Ming Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9809-9815
A novel type of supertetrahedral connectivity is exhibited by the 72‐atom discrete supercubooctahedron in (Cs6Cl)2Cs5[Ga15Ge9Se48] ( 1 ), which undergoes both cation and anion exchange, as revealed by unambiguous single‐crystal X‐ray diffraction data. Electronic‐structure studies helped to understand the Ge/Ga distribution. 相似文献
92.
Tao Wang Dr. Yuzhou Wu Dr. Seah Ling Kuan Oliver Dumele Dr. Markus Lamla Dr. David Y. W. Ng Matthias Arzt Jessica Thomas Jan O. Mueller Prof. Dr. Christopher Barner‐Kowollik Prof. Dr. Tanja Weil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):228-238
A disulfide intercalator toolbox was developed for site‐specific attachment of a broad variety of functional groups to proteins or peptides under mild, physiological conditions. The peptide hormone somatostatin (SST) served as model compound for intercalation into the available disulfide functionalization schemes starting from the intercalator or the reactive SST precursor before or after bioconjugation. A tetrazole–SST derivative was obtained that undergoes photoinduced cycloaddition in mammalian cells, which was monitored by live‐cell imaging. 相似文献
93.
94.
95.
96.
Junshan Jing Yunfei Wu Jun Tao Huizheng Che Xiangao Xia Xiaochun Zhang Peng Yan Deming Zhao Leiming Zhang 《中国颗粒学报》2015,(1):144-154
Year-round measurements of the mass concentration and optical properties of fine aerosols(PM2.5) from June 2009 to May 2010 at an urban site in Beijing were analyzed.The annual mean values of the PM2.5 mass concentration,absorption coefficient(Ab),scattering coefficient(Sc) and single scattering albedo(SSA)at 525 nm were 67±66μg/m3,64 ±62 Mm-1,360 ±405 Mm-1 and 0.82 ±0.09,respectively.The bulk mass absorption efficiency and scattering efficiency of the PM2.5 at 525 nm were 0.78 m2/g and 5.55 m2/g,respectively.The Ab and Sc showed a similar diurnal variation with a maximum at night and a minimum in the afternoon,whereas SSA displayed an opposite diurnal pattern.Significant increases in the Ab and Sc were observed in pollution episodes caused by the accumulation of pollutants from both local and regional sources under unfavorable weather conditions.Aerosol loadings in dust events increased by several times in the spring,which had limited effects on the Ab and Sc due to the low absorption and scattering efficiency of dust particles.The frequency of haze days was the highest in autumn because of the high aerosol absorption and scattering under unfavorable weather conditions.The daily PM2.5concentration should be controlled to a level lower than 64 μg/m3 to prevent the occurrence of haze days according to its exponentially decreased relationship with visibility. 相似文献
97.
98.
Interplay of Hole Transfer and Host–Guest Interaction in a Molecular Dyad and Triad: Ensemble and Single‐Molecule Spectroscopy and Sensing Applications 下载免费PDF全文
Dr. Xiangyang Wu Dr. Fang Liu Dr. Kym L. Wells Serena L. J. Tan Prof. Dr. Richard D. Webster Prof. Dr. Howe‐Siang Tan Prof. Dr. Dawei Zhang Prof. Dr. Bengang Xing Prof. Dr. Edwin K. L. Yeow 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3387-3398
A new molecular dyad consisting of a Cy5 chromophore and ferrocene (Fc) and a triad consisting of Cy5, Fc, and β‐cyclodextrin (CD) are synthesized and their photophysical properties investigated at both the ensemble and single‐molecule levels. Hole transfer efficiency from Cy5 to Fc in the dyad is reduced upon addition of CD. This is due to an increase in the Cy5‐Fc separation (r) when the Fc is encapsulated in the macrocyclic host. On the other hand, the triad adopts either a Fc‐CD inclusion complex conformation in which hole transfer quenching of the Cy5 by Fc is minimal or a quasi‐static conformation with short r and rapid charge transfer. Single‐molecule fluorescence measurements reveal that r is lengthened when the triad molecules are deposited on a glass substrate. By combining intramolecular charge transfer and competitive supramolecular interaction, the triad acts as an efficient chemical sensor to detect different bioactive analytes such as amantadine hydrochloride and sodium lithocholate in aqueous solution and synthetic urine. 相似文献
99.
100.
Ionics - A novel stereoscopic snowflake-like CoO material is synthesized via a simple two-step process, including the hydrothermal process for the formation of the stereoscopic snowflake-like... 相似文献