全文获取类型
收费全文 | 95815篇 |
免费 | 26201篇 |
国内免费 | 19341篇 |
专业分类
化学 | 62648篇 |
晶体学 | 1175篇 |
力学 | 6429篇 |
综合类 | 173篇 |
数学 | 12132篇 |
物理学 | 58800篇 |
出版年
2024年 | 487篇 |
2023年 | 1149篇 |
2022年 | 1465篇 |
2021年 | 1348篇 |
2020年 | 1749篇 |
2019年 | 2257篇 |
2018年 | 2038篇 |
2017年 | 2668篇 |
2016年 | 3117篇 |
2015年 | 3308篇 |
2014年 | 3325篇 |
2013年 | 5339篇 |
2012年 | 6104篇 |
2011年 | 7712篇 |
2010年 | 10431篇 |
2009年 | 10554篇 |
2008年 | 4568篇 |
2007年 | 3977篇 |
2006年 | 3606篇 |
2005年 | 3789篇 |
2004年 | 4395篇 |
2003年 | 3631篇 |
2002年 | 3413篇 |
2001年 | 3589篇 |
2000年 | 2667篇 |
1999年 | 2941篇 |
1998年 | 2472篇 |
1997年 | 2239篇 |
1996年 | 2585篇 |
1995年 | 2962篇 |
1994年 | 2997篇 |
1993年 | 3010篇 |
1992年 | 2602篇 |
1991年 | 2265篇 |
1990年 | 1879篇 |
1989年 | 1974篇 |
1988年 | 1919篇 |
1987年 | 1194篇 |
1986年 | 1257篇 |
1985年 | 912篇 |
1984年 | 1021篇 |
1982年 | 920篇 |
1981年 | 762篇 |
1980年 | 798篇 |
1979年 | 543篇 |
1978年 | 553篇 |
1977年 | 656篇 |
1976年 | 1061篇 |
1973年 | 459篇 |
1972年 | 543篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Cui Shisheng Shanbhag Uday Staudigl Mathias Vuong Phan 《Computational Optimization and Applications》2022,82(2):465-498
Computational Optimization and Applications - We develop a globalized Proximal Newton method for composite and possibly non-convex minimization problems in Hilbert spaces. Additionally, we impose... 相似文献
3.
Li Quanxin Li Zheng He Cheng Sun Huilin Tan Shengheng Zhang Hua 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2105-2115
Journal of Radioanalytical and Nuclear Chemistry - The simplified 8-oxide system (SiO2-B2O3-Na2O-Al2O3-CaO-TiO2-MoO3-La2O3) has been prepared under two types of cooling methods, and analyzed with... 相似文献
5.
Kai Cheng Xiao-Shuai Zhang Jie An Cheng Li Ruo-Yun Zhang Run Ye Prof. Dr. Bang-Jiao Ye Prof. Dr. Bo Liu Prof. Dr. Yuan-Di Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7553-7560
Given their superior penetration depths, photosensitizers with longer absorption wavelengths present broader application prospects in photodynamic therapy (PDT). Herein, Ag2S quantum dots were discovered, for the first time, to be capable of killing tumor cells through the photodynamic route by near-infrared light irradiation, which means relatively less excitation of the probe compared with traditional photosensitizers absorbing short wavelengths. On modification with polydopamine (PDA), PDA-Ag2S was obtained, which showed outstanding capacity for inducing reactive oxygen species (increased by 1.69 times). With the addition of PDA, Ag2S had more opportunities to react with surrounding O2, which was demonstrated by typical triplet electron spin resonance (ESR) analysis. Furthermore, the PDT effects of Ag2S and PDA-Ag2S achieved at longer wavelengths were almost identical to the effects produced at 660 nm, which was proved by studies in vitro. PDA-Ag2S showed distinctly better therapeutic effects than Ag2S in experiments in vivo, which further validated the enhanced regulatory effect of PDA. Altogether, a new photosensitizer with longer absorption wavelength was developed by using the hitherto-unexplored photodynamic function of Ag2S quantum dots, which extended and enhanced the regulatory effect originating from PDA. 相似文献
6.
量子自旋液体是最近几年刚被人们证实除铁磁体、反铁磁体之外的第三种磁性类型,因其有望解释高温超导的运行机制、改变计算机硬盘信息存储方式而在物理、材料等领域备受关注。自旋阻挫作为量子自旋液体的最小单元可能是解开量子自旋液体诸多问题的钥匙,所以在磁学、电学研究领域再一次成为人们研究的热点。基于文献报道的三核铜配合物[Cu3(μ3-OH)(μ-OPz)3(NO3)2(H2O)2]·CH3OH(1),我们合成了三维金属有机框架配合物{[Ag(HOPz)Cu3(μ3-OH)(NO3)3(OPz)2Ag(NO3)]·6H2O}n(2)(HOPz=甲基(2-吡嗪基)酮肟),并从自旋阻挫的角度对二者磁性质进行对比和详细分析。磁化率数据表明自旋间有很强的反铁磁相互作用和反对称交换。通过包含各向同性和反对称交换的哈密顿算符对两者磁学数据进行拟合并研究其磁构关系,所获最佳拟合参数为:配合物1:Jav=-426 cm^-1,g⊥=1.83,g∥=2.00;配合物2:Jav=-401 cm^-1,g⊥=1.85,g∥=2.00。 相似文献
7.
8.
Panpan Li Quanbin Liang Eugene Yau-Hin Hong Chin-Yiu Chan Yat-Hin Cheng Ming-Yi Leung Mei-Yee Chan Kam-Hung Low Hongbin Wu Vivian Wing-Wah Yam 《Chemical science》2020,11(42):11601
A class of acceptor–donor–acceptor chromophoric small-molecule non-fullerene acceptors, 1–4, with difluoroboron(iii) β-diketonate (BF2bdk) as the electron-accepting moiety has been developed. Through the variation of the central donor unit and the modification on the peripheral substituents of the terminal BF2bdk acceptor unit, their photophysical and electrochemical properties have been systematically studied. Taking advantage of their low-lying lowest unoccupied molecular orbital energy levels (from −3.65 to −3.72 eV) and relatively high electron mobility (7.49 × 10−4 cm2 V−1 s−1), these BF2bdk-based compounds have been employed as non-fullerene acceptors in organic solar cells with maximum power conversion efficiencies of up to 4.31%. Moreover, bistable resistive memory characteristics with charge-trapping mechanisms have been demonstrated in these BF2bdk-based compounds. This work not only demonstrates for the first time the use of a boron(iii) β-diketonate unit in constructing non-fullerene acceptors, but also provides more insights into designing organic materials with multi-functional properties.Boron(iii) β-diketonates have been demonstrated to serve as multi-functional materials in NFA-based OPVs and organic resistive memories. 相似文献
9.
Wu Shang-Zhuo Yu Qiang Li Yue-Hua Cui Guang-Hua 《Research on Chemical Intermediates》2021,47(2):835-851
Research on Chemical Intermediates - Combination of three aromatic carboxylic acids (5-nitroisophthalic acid (H2nip), 2,6-naphthalenedicarboxylic acid (H2ndc), tetrabromoterephthalic acid (H2tbta))... 相似文献
10.