全文获取类型
收费全文 | 15953篇 |
免费 | 2569篇 |
国内免费 | 1774篇 |
专业分类
化学 | 11778篇 |
晶体学 | 199篇 |
力学 | 885篇 |
综合类 | 82篇 |
数学 | 1665篇 |
物理学 | 5687篇 |
出版年
2024年 | 16篇 |
2023年 | 323篇 |
2022年 | 350篇 |
2021年 | 521篇 |
2020年 | 652篇 |
2019年 | 665篇 |
2018年 | 602篇 |
2017年 | 522篇 |
2016年 | 758篇 |
2015年 | 796篇 |
2014年 | 995篇 |
2013年 | 1232篇 |
2012年 | 1453篇 |
2011年 | 1554篇 |
2010年 | 1116篇 |
2009年 | 960篇 |
2008年 | 1076篇 |
2007年 | 979篇 |
2006年 | 876篇 |
2005年 | 757篇 |
2004年 | 564篇 |
2003年 | 462篇 |
2002年 | 432篇 |
2001年 | 313篇 |
2000年 | 318篇 |
1999年 | 264篇 |
1998年 | 220篇 |
1997年 | 198篇 |
1996年 | 177篇 |
1995年 | 145篇 |
1994年 | 193篇 |
1993年 | 132篇 |
1992年 | 127篇 |
1991年 | 96篇 |
1990年 | 90篇 |
1989年 | 84篇 |
1988年 | 44篇 |
1987年 | 31篇 |
1986年 | 35篇 |
1985年 | 29篇 |
1984年 | 22篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 7篇 |
1980年 | 17篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 7篇 |
1967年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Houfu Lv Dr. Tianfu Liu Dr. Xiaomin Zhang Dr. Yuefeng Song Hiroaki Matsumoto Prof. Dr. Na Ta Chaobin Zeng Prof. Dr. Guoxiong Wang Prof. Dr. Xinhe Bao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16102-16107
In situ exsolution of metal nanoparticles in perovskite under reducing atmosphere is employed to generate a highly active metal–oxide interface for CO2 electrolysis in a solid oxide electrolysis cell. Atomic-scale insight is provided into the exsolution of CoFe alloy nanoparticles in La0.4Sr0.6Co0.2Fe0.7Mo0.1O3−δ (LSCFM) by in situ scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy and DFT calculations. The doped Mo atoms occupy B sites of LSCFM, which increases the segregation energy of Co and Fe ions at B sites and improves the structural stability of LSCFM under a reducing atmosphere. In situ STEM measurements visualized sequential exsolution of Co and Fe ions, formation of CoFe alloy nanoparticles, and reversible exsolution and dissolution of CoFe alloy nanoparticles in LSCFM. The metal–oxide interface improves CO2 adsorption and activation, showing a higher CO2 electrolysis performance than the LSCFM counterparts. 相似文献
992.
Prof. Meng Su Feifei Qin Zeying Zhang Bingda Chen Qi Pan Dr. Zhandong Huang Zheren Cai Zhipeng Zhao Prof. Xiaotian Hu Prof. Dominique Derome Prof. Jan Carmeliet Prof. Yanlin Song 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(34):14340-14346
A key issue of micro/nano devices is how to integrate micro/nanostructures with specified chemical components onto various curved surfaces. Hydrodynamic printing of micro/nanostructures on three-dimensional curved surfaces is achieved with a strategy that combines template-induced hydrodynamic printing and self-assembly of nanoparticles (NPs). Non-lithography flexible wall-shaped templates are replicated with microscale features by dicing a trench-shaped silicon wafer. Arising from the capillary pumped function between the template and curved substrates, NPs in the colloidal suspension self-assemble into close-packed micro/nanostructures without a gravity effect. Theoretical analysis with the lattice Boltzmann model reveals the fundamental principles of the hydrodynamic assembly process. Spiral linear structures achieved by two kinds of fluorescent NPs show non-interfering photoluminescence properties, while the waveguide and photoluminescence are confirmed in 3D curved space. The printed multiconstituent micro/nanostructures with single-NP resolution may serve as a general platform for optoelectronics beyond flat surfaces. 相似文献
993.
Guoyu Zhang Song Zhou Dr. Liang Fu Dr. Pinhong Chen Prof. Yibiao Li Prof. Dr. Jianping Zou Prof. Dr. Guosheng Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20619-20624
The first copper-catalyzed asymmetric cyanation and etherification reactions of enamides have been established, where a carbon-centered radical adjacent to a nitrogen atom (CRAN) is enantioselectively trapped by a chiral copper(II) species. Moreover, the asymmetric cyanation of vinyl esters was disclosed as well. These reactions feature very mild reaction conditions and high functional group tolerance, and give a series of chiral α-cyano amides, α-cyano esters and α-hemiaminals in good yields with excellent enantioselectivity. The chiral α-cyano amides can be easily converted into enantioenriched 1,2-diamines and amino acids. 相似文献
994.
Yun Liu Guangze Yang Song Jin Run Zhang Peng Chen Tengjisi Lianzhou Wang Dong Chen David A. Weitz Chun-Xia Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20240-20249
Understanding drug-release kinetics is critical for the development of drug-loaded nanoparticles. We developed a J-aggregate-based Förster-resonance energy-transfer (FRET) method to investigate the release of novel high-drug-loading (50 wt %) nanoparticles in comparison with low-drug-loading (0.5 wt %) nanoparticles. Single-dye-loaded nanoparticles form J-aggregates because of the high dye-loading (50 wt %), resulting in a large red-shift (≈110 nm) in the fluorescence spectrum. Dual-dye-loaded nanoparticles with high dye-loading using FRET pairs exhibited not only FRET but also a J-aggregate red-shift (116 nm). Using this J-aggregate-based FRET method, dye-core–polymer-shell nanoparticles showed two release processes intracellularly: the dissolution of the dye aggregates into dye molecules and the release of the dye molecules from the polymer shell. Also, the high-dye-loading nanoparticles (50 wt %) exhibited a slow release kinetics in serum and relatively quick release in cells, demonstrating their great potential in drug delivery. 相似文献
995.
Xuan Zhou Dr. Kai Li Yunxiang Lin Prof. Li Song Jincheng Liu Yu Liu Lingling Zhang Prof. Zhijian Wu Prof. Shuyan Song Prof. Jun Li Prof. Hongjie Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13670-13676
Synthesis of well-defined atomically mixed alloy nanoparticles on desired substrates is an ultimate goal for their practical application. Herein we report a general approach for preparing atomically mixed AuPt, AuPd, PtPd, AuPtPd NAs(nanoalloys) through single-atom level manipulation. By utilizing the ubiquitous tendency of aggregation of single atoms into nanoparticles at elevated temperatures, we have synthesized nanoalloys on a solid solvent with CeO2 as a carrier and transition-metal single atoms as an intermediate state. The supported nanoalloys/CeO2 with ultra-low noble metal content (containing 0.2 wt % Au and 0.2 wt % Pt) exhibit enhanced catalytic performance towards complete CO oxidation at room temperature and remarkable thermostability. This work provides a general strategy for facile and rapid synthesis of well-defined atomically mixed nanoalloys that can be applied for a range of emerging techniques. 相似文献
996.
Xiangyu Ma Yuyuan Bai Yongbo Song Qinzhen Li Ying Lv Hui Zhang Prof. Haizhu Yu Prof. Manzhou Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17387-17391
Precise atomic structure of metal nanoclusters (NCs) is fundamental for elucidating the structure–property relationships and the inherent size-evolution principles. Reported here is the largest known FCC-based (FCC=face centered cubic) silver nanocluster, [Ag100(SC6H33,4F2)48(PPh3)8]−: the first all-octahedral symmetric nesting Ag nanocluster with a four-layered Ag6@Ag38@Ag48S24@Ag8S24P8 structure, consistent symmetry elements, and a unique rhombicuboctahedral morphology distinct from theoretical predictions and previously reported FCC-based Ag clusters. DFT studies revealed extensive interlayer interactions and degenerate frontier orbitals. The FCC-based Russian nesting doll model constitutes a new platform for the study of the size-evolution principles of Ag NCs. 相似文献
997.
998.
Youngjun Song Dr. Sunyoung Kang Sangyoon Kang Prof. Dr. Yan Lee 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23168-23172
We report the synthesis of new helical polymeric structures having alternating cis and trans double bonds and chiral amino acid side chains by metathesis cyclopolymerization. The polymer helicity, which is generated by the interaction between fluorenylmethyloxycarbonyl (Fmoc) groups in the side chains, is dramatically affected by solvents. A thorough experimental and theoretical analysis including nuclear magnetic resonance, atomic force microscopy, and density functional theory and molecular mechanics calculations suggests that the helicity of both backbone and side chains are determined by anti-syn rotation of the carbamate groups and by the different interactions of the Fmoc groups with solvents. 相似文献
999.
Dr. Song Jin Youxuan Ni Zhimeng Hao Prof. Kai Zhang Dr. Yong Lu Dr. Zhenhua Yan Dr. Yajuan Wei Dr. Ying-Rui Lu Dr. Ting-Shan Chan Prof. Jun Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22069-22073
A general graphene quantum dot-tethering design strategy to synthesize single-atom catalysts (SACs) is presented. The strategy is applicable to different metals (Cr, Mn, Fe, Co, Ni, Cu, and Zn) and supports (0D carbon nanosphere, 1D carbon nanotube, 2D graphene nanosheet, and 3D graphite foam) with the metal loading of 3.0–4.5 wt %. The direct transmission electron microscopy imaging and X-ray absorption spectra analyses confirm the atomic dispersed metal in carbon supports. Our study reveals that the abundant oxygenated groups for complexing metal ions and the rich defective sites for incorporating nitrogen are essential to realize the synthesis of SACs. Furthermore, the carbon nanotube supported Ni SACs exhibits high electrocatalytic activity for CO2 reduction with nearly 100 % CO selectivity. This universal strategy is expected to open up new research avenues to produce SACs for diverse electrocatalytic applications. 相似文献
1000.
Guifa Zhai Wenyan Wang Dr. Wei Xu Guo Sun Chaoqun Hu Xiangming Wu Zisong Cong Liang Deng Yanrong Shi Prof. Dr. Peter F. Leadlay Prof. Dr. Heng Song Prof. Dr. Kui Hong Prof. Dr. Zixin Deng Prof. Dr. Yuhui Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22926-22930
The colinearity of canonical modular polyketide synthases, which creates a direct link between multienzyme structure and the chemical structure of the biosynthetic end-product, has become a cornerstone of knowledge-based genome mining. Herein, we report genetic and enzymatic evidence for the remarkable role of an enoylreductase in the polyketide synthase for azalomycin F biosynthesis. This internal enoylreductase domain, previously identified as acting only in the second of two chain extension cycles on an initial iterative module, is shown to also catalyze enoylreduction in trans within the next module. The mechanism for this rare deviation from colinearity appears to involve direct cross-modular interaction of the reductase with the longer acyl chain, rather than back transfer of the substrate into the iterative module, suggesting an additional and surprising plasticity in natural PKS assembly-line catalysis. 相似文献