全文获取类型
收费全文 | 9981篇 |
免费 | 1453篇 |
国内免费 | 1240篇 |
专业分类
化学 | 7228篇 |
晶体学 | 92篇 |
力学 | 620篇 |
综合类 | 84篇 |
数学 | 1061篇 |
物理学 | 3589篇 |
出版年
2024年 | 37篇 |
2023年 | 196篇 |
2022年 | 314篇 |
2021年 | 356篇 |
2020年 | 365篇 |
2019年 | 350篇 |
2018年 | 279篇 |
2017年 | 265篇 |
2016年 | 454篇 |
2015年 | 399篇 |
2014年 | 564篇 |
2013年 | 676篇 |
2012年 | 816篇 |
2011年 | 860篇 |
2010年 | 583篇 |
2009年 | 572篇 |
2008年 | 672篇 |
2007年 | 565篇 |
2006年 | 486篇 |
2005年 | 493篇 |
2004年 | 364篇 |
2003年 | 336篇 |
2002年 | 354篇 |
2001年 | 295篇 |
2000年 | 250篇 |
1999年 | 211篇 |
1998年 | 197篇 |
1997年 | 171篇 |
1996年 | 166篇 |
1995年 | 131篇 |
1994年 | 150篇 |
1993年 | 106篇 |
1992年 | 120篇 |
1991年 | 104篇 |
1990年 | 76篇 |
1989年 | 78篇 |
1988年 | 45篇 |
1987年 | 31篇 |
1986年 | 38篇 |
1985年 | 26篇 |
1984年 | 16篇 |
1983年 | 18篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Some supramolecular polyacrylate-based liquid crystal polymers (PLCPs) were prepared by polyacrylic acid, a liquid crystal monomer and 3,5-pyridinedicarboxylic acid. Series of magnetic liquid crystal particles (Fe3O4@PLCPs) with core-shell structure were prepared by modifying surface of magnetic nanoparticles Fe3O4 by the PLCPs. The Fe3O4@PLCPs showed a saturation magnetization strength above 51.17 emu/g, which is similar to pure magnetic Fe3O4, indicating good magnetism and magnetic field dependence. Series of magnetorheological fluids were fabricated by Fe3O4@PLCPs (using as dispersed phase) and silicone oil (using as carrier liquid). The effects of mesogen, magnetic particle, and the polymer matrix on magnetorheological performance and settling stability were investigated. The magnetorheological fluid based on 10% Fe3O4@PLCP-1 showed the best performance at an applied magnetic field of 100 mT in this study. Furthermore, the magnetorheological fluids showed excellent settling stability because the density of Fe3O4@PLCPs was lower than that of Fe3O4. The Fe3O4@PLCPs-based fluids presented certain application potential in the field of magnetic fluid due to the excellent magnetorheological effect and settling stability. 相似文献
952.
Zhipeng Xiang Wenjin Li Kai Wan Zhiyong Fu Zhenxing Liang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202214601
Molecule aggregation in solution is acknowledged to be universal and can regulate the molecule's physiochemical properties, which however has been rarely investigated in electrochemistry. Herein, an electrochemical method is developed to quantitatively study the aggregation behavior of the target molecule methyl viologen dichloride. It is found that the oxidation state dicationic ions stay discrete, while the singly-reduced state monoradicals yield a concentration-dependent aggregation behavior. As a result, the molecule's energy level and its redox potential can be effectively regulated. This work does not only provide a method to investigate the molecular aggregation, but also demonstrates the feasibility to tune redox flow battery's performance by regulating the aggregation behavior. 相似文献
953.
Dr. Xiaolong Zu Yuan Zhao Dr. Xiaodong Li Runhua Chen Weiwei Shao Li Li Panzhe Qiao Prof. Wensheng Yan Prof. Yang Pan Qian Xu Prof. Junfa Zhu Prof. Yongfu Sun Prof. Yi Xie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202215247
Herein, we first design a model of reversible redox-switching metal–organic framework single-unit-cell sheets, where the abundant metal single sites benefit for highly selective CO2 reduction, while the reversible redox-switching metal sites can effectively activate CO2 molecules. Taking the synthetic Cu-MOF single-unit-cell sheets as an example, synchrotron-radiation quasi in situ X-ray photoelectron spectra unravel the reversible switching CuII/CuI single sites initially accept photoexcited electrons and then donate them to CO2 molecules, which favors the rate-liming activation into CO2δ−, verified by in situ FTIR spectra and Gibbs free energy calculations. As an outcome, Cu-MOF single-unit-cell sheets achieve near 100 % selectivity for CO2 photoreduction to CO with a high rate of 860 μmol g−1 h−1 without any sacrifice reagent or photosensitizer, where both the activity and selectivity outperform previously reported photocatalysts evaluated under similar conditions. 相似文献
954.
Dr. Xiaofei Yang Dr. Xuejie Gao Dr. Ming Jiang Dr. Jing Luo Jitong Yan Jiamin Fu Dr. Hui Duan Dr. Shangqian Zhao Prof. Yongfu Tang Dr. Rong Yang Ruying Li Prof. Jiantao Wang Dr. Huan Huang Prof. Chandra Veer Singh Prof. Xueliang Sun 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215680
Sulfide electrolytes with high ionic conductivities are one of the most highly sought for all-solid-state lithium batteries (ASSLBs). However, the non-negligible electronic conductivities of sulfide electrolytes (≈10−8 S cm−1) lead to electron smooth transport through the sulfide electrolyte pellets, resulting in Li dendrite directly depositing at the grain boundaries (GBs) and serious self-discharge. Here, a grain-boundary electronic insulation (GBEI) strategy is proposed to block electron transport across the GBs, enabling Li−Li symmetric cells with 30 times longer cycling life and Li−LiCoO2 full cells with three times lower self-discharging rate than pristine sulfide electrolytes. The Li−LiCoO2 ASSLBs deliver high capacity retention of 80 % at 650 cycles and stable cycling performance for over 2600 cycles at 0.5 mA cm−2. The innovation of the GBEI strategy provides a new direction to pursue high-performance ASSLBs via tailoring the electronic conductivity. 相似文献
955.
Dr. Liping Liu Dr. Haibing Meng Dr. Yongqiang Chai Dr. Xianjie Chen Dr. Jingyi Xu Dr. Xiaolong Liu Dr. Weixu Liu Prof. Dirk M. Guldi Prof. Yongfa Zhu 《Angewandte Chemie (International ed. in English)》2023,62(11):e202217897
High-efficiency photocatalysts based on metal-organic frameworks (MOFs) are often limited by poor charge separation and slow charge-transfer kinetics. Herein, a novel MOF photocatalyst is successfully constructed by encapsulating C60 into a nano-sized zirconium-based MOF, NU-901. By virtue of host-guest interactions and uneven charge distribution, a substantial electrostatic potential difference is set-up in C60@NU-901. The direct consequence is a robust built-in electric field, which tends to be 10.7 times higher in C60@NU-901 than that found in NU-901. In the catalyst, photogenerated charge carriers are efficiently separated and transported to the surface. For example, photocatalytic hydrogen evolution reaches 22.3 mmol g−1 h−1 for C60@NU-901, which is among the highest values for MOFs. Our concept of enhancing charge separation by harnessing host-guest interactions constitutes a promising strategy to design photocatalysts for efficient solar-to-chemical energy conversion. 相似文献
956.
Dr. Huanhuan Shi Prof. Mengmeng Li Shuai Fu Dr. Christof Neumann Dr. Xiaodong Li Dr. Wenhui Niu Yunji Lee Prof. Mischa Bonn Dr. Hai I. Wang Prof. Andrey Turchanin Dr. Ali Shaygan Nia Dr. Sheng Yang Prof. Xinliang Feng 《Angewandte Chemie (International ed. in English)》2023,62(28):e202303929
Two-dimensional van der Waals heterostructures (2D vdWHs) have recently gained widespread attention because of their abundant and exotic properties, which open up many new possibilities for next-generation nanoelectronics. However, practical applications remain challenging due to the lack of high-throughput techniques for fabricating high-quality vdWHs. Here, we demonstrate a general electrochemical strategy to prepare solution-processable high-quality vdWHs, in which electrostatic forces drive the stacking of electrochemically exfoliated individual assemblies with intact structures and clean interfaces into vdWHs with strong interlayer interactions. Thanks to the excellent combination of strong light absorption, interfacial charge transfer, and decent charge transport properties in individual layers, thin-film photodetectors based on graphene/In2Se3 vdWHs exhibit great promise for near-infrared (NIR) photodetection, owing to a high responsivity (267 mA W−1), fast rise (72 ms) and decay (426 ms) times under NIR illumination. This approach enables various hybrid systems, including graphene/In2Se3, graphene/MoS2 and graphene/MoSe2 vdWHs, providing a broad avenue for exploring emerging electronic, photonic, and exotic quantum phenomena. 相似文献
957.
Jiahui Zeng Yu Fu Yue Wu Shanshan Wang Wenxiang Zhang Prof. Heping Ma 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310235
Xe is an ideal anesthetic gas, but it has not been widely used in practice due to its high cost and low output. Closed-circuit Xe recovery and recycling is an economically viable method to ensure adequate supply in medical use. Herein, we design an innovative way to recover Xe by using a stable fluorinated metal-organic framework (MOF) NbOFFIVE-1-Ni to eliminate CO2 from moist exhaled anesthetic gases. Unlike other Xe recovery MOFs with low Xe/CO2 selectivity (less than 10), NbOFFIVE-1-Ni could achieve absolute molecular sieve separation of CO2/Xe with excellent CO2 selectivity (825). Mixed-gas breakthrough experiments assert the potential of NbOFFIVE-1-Ni as a molecular sieve adsorbent for the effective and energy-efficient removal of carbon dioxide with 99.16 % Xe recovery. Absolute CO2/Xe separation in NbOFFIVE-1-Ni makes closed-circuit Xe recovery and recycling can be easily realized, demonstrating the potential of NbOFFIVE-1-Ni for important anesthetic gas regeneration under ambient conditions. 相似文献
958.
Di Wu Dandan Ge Yingping Dai Yanchun Chen Qing Fu Yu Jin 《Journal of separation science》2023,46(14):2300156
In this paper, an off-line combination method of supercritical fluid extraction and supercritical fluid chromatography was developed for the selective extraction and isolation of diphenylheptanes and flavonoids from Alpinia officinarum Hance. The enrichment of target components was successfully achieved using supercritical fluid extraction with the following conditions (8% ethanol as co-solvent at 45°C and 30 MPa for 30 min). Taking full advantage of the complementarity of supercritical fluid chromatography stationary phases, a two-step preparative supercritical fluid chromatography strategy was constructed. The extract was firstly divided into seven fractions on a Diol column (250 × 20 mm internal diameter, 10 μm) within 8 min by gradient elution increasing from 5% to 20% modifier (methanol) at 55 ml/min and 15 MPa. Then the seven fractions were separated by using a 1-AA or a DEA column (250 × 19 mm internal diameter, 5 μm) at 50 ml/min and 13.5 MPa. This two-step strategy showed superior separation ability for structural analogs. As a result, seven compounds, including four diphenylheptanes and three flavonoids with high purity, were successfully obtained. The developed method is also helpful for the extraction and isolation of other structural analogs of traditional Chinese medicines. 相似文献
959.
Hongmin Wang Shuting Fu Bo Shang Sungho Jeon Yiren Zhong Nia J. Harmon Chungseok Choi Eric A. Stach Hailiang Wang 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305251
Photothermal CO2 reduction is one of the most promising routes to efficiently utilize solar energy for fuel production at high rates. However, this reaction is currently limited by underdeveloped catalysts with low photothermal conversion efficiency, insufficient exposure of active sites, low active material loading, and high material cost. Herein, we report a potassium-modified carbon-supported cobalt (K+−Co−C) catalyst mimicking the structure of a lotus pod that addresses these challenges. As a result of the designed lotus-pod structure which features an efficient photothermal C substrate with hierarchical pores, an intimate Co/C interface with covalent bonding, and exposed Co catalytic sites with optimized CO binding strength, the K+−Co−C catalyst shows a record-high photothermal CO2 hydrogenation rate of 758 mmol gcat−1 h−1 (2871 mmol gCo−1 h−1) with a 99.8 % selectivity for CO, three orders of magnitude higher than typical photochemical CO2 reduction reactions. We further demonstrate with this catalyst effective CO2 conversion under natural sunlight one hour before sunset during the winter season, putting forward an important step towards practical solar fuel production. 相似文献
960.
Dr. Wei-Hua Deng Prof. Qiao-Hong Li Jie Chen Chuan-Zhe Wang Dr. Zhi-Hua Fu Dr. Xiao-Liang Ye Prof. Guan-E Wang Prof. Gang Xu 《Angewandte Chemie (International ed. in English)》2023,62(31):e202305977
The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H2O on the EC of MOFs is rarely reported. We explored the effect of H2O on the EC in the MOFs (NH2)2-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 107 on H2SO4@(NH2)2-MIL-125 by H2O was observed. Brønsted acid–base pairs formed with the −NH2 groups, and H2SO4 played an important role in promoting the charge transfer from H2O to the MOF. Based on H2SO4@(NH2)2-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H2O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials. 相似文献