全文获取类型
收费全文 | 1104篇 |
免费 | 173篇 |
国内免费 | 149篇 |
专业分类
化学 | 842篇 |
晶体学 | 18篇 |
力学 | 70篇 |
数学 | 81篇 |
物理学 | 415篇 |
出版年
2024年 | 3篇 |
2023年 | 25篇 |
2022年 | 45篇 |
2021年 | 57篇 |
2020年 | 45篇 |
2019年 | 55篇 |
2018年 | 33篇 |
2017年 | 39篇 |
2016年 | 55篇 |
2015年 | 64篇 |
2014年 | 73篇 |
2013年 | 79篇 |
2012年 | 101篇 |
2011年 | 121篇 |
2010年 | 63篇 |
2009年 | 66篇 |
2008年 | 54篇 |
2007年 | 55篇 |
2006年 | 60篇 |
2005年 | 41篇 |
2004年 | 48篇 |
2003年 | 31篇 |
2002年 | 26篇 |
2001年 | 13篇 |
2000年 | 22篇 |
1999年 | 28篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 11篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有1426条查询结果,搜索用时 15 毫秒
91.
Bian HD Gu W Xu JY Bian F Yan SP Liao DZ Jiang ZH Cheng P 《Inorganic chemistry》2003,42(14):4265-4267
The first mu(3)-oxalato-bridged copper(II) complex, [[Cu(3)(L)(3)(mu(3)-C(2)O(4))][Cu(L)(H(2)O)](ClO(4))(2)] x 0.5(H(2)O) x 0.5(CH(3)OH), where HL = N-ethyl-N'-salicylidene-1,2-diaminoethane, has been synthesized and characterized by variable-temperature magnetic susceptibility measurement. The complex exhibits ferromagnetic coupling between the oxalato-bridged copper atoms and antiferromagnetic coupling between the oxygen-bridged copper atoms. 相似文献
92.
93.
94.
Xuanang Bian Dr. Yunxuan Zhao Dr. Chao Zhou Prof. Tierui Zhang 《Angewandte Chemie (International ed. in English)》2023,62(24):e202219340
Enormous advances in photothermal catalysis have been made over the years, whereas the temperature assessment still remains controversial in the majority of photothermal catalytic systems. Herein, we methodically uncovered the phenomenon of temperature determination bias arising from prominent temperature differences in gas-solid photothermal catalytic systems, which extensively existed yet has been overlooked in most relevant cases. To avoid the interference of temperature bias, we developed a universal protocol for reliable temperature evaluation of gas-solid photothermal catalytic reactions, with emphasis on eliminating the temperature gradient and temperature fluctuation of catalyst layer via optimizing the reaction system. This work presents a functional and credible practice for temperature detection, calling attention to addressing the effects of temperature differences, and reassessing the actual temperature-based performances in gas-solid photothermal catalysis. 相似文献
95.
Yuan-Zhe Cheng Wenyan Ji Peng-Yuan Hao Xue-Han Qi Xianxin Wu Xiao-Meng Dou Xin-Yue Bian Di Jiang Prof. Dr. Fa-Tang Li Prof. Dr. Xin-Feng Liu Dr. Dong-Hui Yang Dr. Xuesong Ding Prof. Dr. Bao-Hang Han 《Angewandte Chemie (International ed. in English)》2023,62(36):e202308523
Constructing a powerful photocatalytic system that can achieve the carbon dioxide (CO2) reduction half-reaction and the water (H2O) oxidation half-reaction simultaneously is a very challenging but meaningful task. Herein, a porous material with a crystalline topological network, named viCOF-bpy-Re, was rationally synthesized by incorporating rhenium complexes as reductive sites and triazine ring structures as oxidative sites via robust −C=C− bond linkages. The charge-separation ability of viCOF-bpy-Re is promoted by low polarized π-bridges between rhenium complexes and triazine ring units, and the efficient charge-separation enables the photogenerated electron–hole pairs, followed by an intramolecular charge-transfer process, to form photogenerated electrons involved in CO2 reduction and photogenerated holes that participate in H2O oxidation simultaneously. The viCOF-bpy-Re shows the highest catalytic photocatalytic carbon monoxide (CO) production rate (190.6 μmol g−1 h−1 with about 100 % selectivity) and oxygen (O2) evolution (90.2 μmol g−1 h−1) among all the porous catalysts in CO2 reduction with H2O as sacrificial agents. Therefore, a powerful photocatalytic system was successfully achieved, and this catalytic system exhibited excellent stability in the catalysis process for 50 hours. The structure–function relationship was confirmed by femtosecond transient absorption spectroscopy and density functional theory calculations. 相似文献
96.
Xiang Chen Dr. Shuhui Guan Jianjiang Zhou Hengjun Shang Jingyuan Zhang Fujian Lv Prof. Han Yu Prof. Dr. Hexing Li Prof. Zhenfeng Bian 《Angewandte Chemie (International ed. in English)》2023,62(45):e202312734
Single-atom catalysts (SACs) have emerged as crucial players in catalysis research, prompting extensive investigation and application. The precise control of metal atom nucleation and growth has garnered significant attention. In this study, we present a straightforward approach for preparing SACs utilizing a photocatalytic radical control strategy. Notably, we demonstrate for the first time that radicals generated during the photochemical process effectively hinder the aggregation of individual atoms. By leveraging the cooperative anchoring of nitrogen atoms and crystal lattice oxygen on the support, we successfully stabilize the single atom. Our Pd1/TiO2 catalysts exhibit remarkable catalytic activity and stability in the Suzuki–Miyaura cross-coupling reaction, which was 43 times higher than Pd/C. Furthermore, we successfully depose Pd atoms onto various substrates, including TiO2, CeO2, and WO3. The photocatalytic radical control strategy can be extended to other single-atom catalysts, such as Ir, Pt, Rh, and Ru, underscoring its broad applicability. 相似文献
97.
Fast atom bombardment mass spectra of a series of arenediazonium salts with various substituents complexed with 18-crown-6 and dibenzo-24-crown-8 ethers were examined. The correlation between quasi-molecular ion abundance of various complexes and the properties, coordination ability of donor-acceptor linkages in the complexes were studied. By using molecular orbital calculation we have successfully demonstrated that the correlation cited is related to the electron cloud densities on the heteroatoms α-N and β-N of arenediazonium salts. 相似文献
98.
本文设计开发了一种以2,6-二甲酰基对甲苯酚为母体的新型荧光探针HMI,可用于高效识别EtOH-H2O (8/2, v/v, HEPES 10 mM, pH =7.4)体系中的CO32-。HMI在660 nm处显示发射带,加入CO32-后,在600 nm的等吸收点激发时,原来在660 nm处的荧光淬灭,而以540 nm为中心的新发射带荧光显着增加,为比率型荧光探针。HMI对CO32-表现出高选择性且具有较强的抗干扰能力。此外,荧光探针HMI对CO32-荧光响应的检测限较低,可达到3.938×10-6 M。更具有意义的是,HMI探针对CO32-的检测能够在实际水样中起到很好的应用,而且细胞成像研究表明,HMI可用于活体MCF-7细胞中CO32-的成像。 相似文献
99.
100.
A new asymmetric Salamo‐based ligand H2L was synthesized using 3‐tert‐butyl‐salicylaldehyde and 6‐methoxy‐2‐[O‐(1‐ethyloxyamide)]‐oxime‐1‐phenol. By adjusting the ratio of the ligand H2L and Cu (II), Co (II), and Ni (II) ions, mononuclear, dinuclear, and trinuclear transition metal (II) complexes, [Cu(L)], [{Co(L)}2], and [{Ni(L)(CH3COO)(CH3CH2OH)}2Ni] with the ligand H2L possessing completely different coordination modes were obtained, respectively. The optical spectra of ligand H2L and its Cu (II), Co (II) and Ni (II) complexes were investigated. The Cu (II) complex is a mononuclear structure, and the Cu (II) atom is tetracoordinated to form a planar quadrilateral structure. The Co (II) complex is dinuclear, and the two Co (II) atoms are pentacoordinated and have coordination geometries of distorted triangular bipyramid. The Ni (II) complex is a trinuclear structure, and the terminal and central Ni (II) atoms are all hexacoordinated, forming distorted octahedral geometries. Furthermore, optical properties including UV–Vis, IR, and fluorescence of the Cu (II), Co (II), and Ni (II) complexes were investigated. Finally, the antibacterial activities of the Cu (II), Co (II), and Ni (II) complexes were explored. According to the experimental results, the inhibitory effect was found to be enhanced with increasing concentrations of the Cu (II), Co (II), and Ni (II) complexes. 相似文献