全文获取类型
收费全文 | 3826篇 |
免费 | 432篇 |
国内免费 | 313篇 |
专业分类
化学 | 2468篇 |
晶体学 | 26篇 |
力学 | 194篇 |
综合类 | 20篇 |
数学 | 491篇 |
物理学 | 1372篇 |
出版年
2023年 | 49篇 |
2022年 | 62篇 |
2021年 | 85篇 |
2020年 | 128篇 |
2019年 | 98篇 |
2018年 | 99篇 |
2017年 | 94篇 |
2016年 | 128篇 |
2015年 | 138篇 |
2014年 | 164篇 |
2013年 | 234篇 |
2012年 | 323篇 |
2011年 | 290篇 |
2010年 | 223篇 |
2009年 | 194篇 |
2008年 | 260篇 |
2007年 | 215篇 |
2006年 | 195篇 |
2005年 | 161篇 |
2004年 | 128篇 |
2003年 | 112篇 |
2002年 | 88篇 |
2001年 | 84篇 |
2000年 | 92篇 |
1999年 | 62篇 |
1998年 | 62篇 |
1997年 | 49篇 |
1996年 | 70篇 |
1995年 | 51篇 |
1994年 | 58篇 |
1993年 | 52篇 |
1992年 | 54篇 |
1991年 | 35篇 |
1990年 | 28篇 |
1989年 | 41篇 |
1988年 | 36篇 |
1987年 | 30篇 |
1986年 | 41篇 |
1985年 | 30篇 |
1984年 | 34篇 |
1983年 | 26篇 |
1982年 | 20篇 |
1981年 | 14篇 |
1980年 | 22篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1976年 | 17篇 |
1975年 | 17篇 |
1973年 | 9篇 |
排序方式: 共有4571条查询结果,搜索用时 31 毫秒
21.
Dr. Jacky C. H. Chu Dr. Clarence T. T. Wong Prof. Dennis K. P. Ng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202214473
Targeted delivery and specific activation of photosensitizers can greatly improve the treatment outcome of photodynamic therapy. To this end, we report herein a novel dual receptor-mediated bioorthogonal activation approach to enhance the tumor specificity of the photodynamic action. It involves the targeted delivery of a biotinylated boron dipyrromethene (BODIPY)-based photosensitizer, which is quenched in the native form by the attached 1,2,4,5-tetrazine unit, and an epidermal growth factor receptor (EGFR)-targeting cyclic peptide conjugated with a bicycle[6.1.0]non-4-yne moiety. Only for cancer cells that overexpress both the biotin receptor and EGFR, the two components can be internalized preferentially where they undergo an inverse electron-demand Diels–Alder reaction, leading to restoration of the photodynamic activity of the BODIPY core. By using a range of cell lines with different expression levels of these two receptors, we have demonstrated that this stepwise “deliver-and-click” approach can confine the photodynamic action on a specific type of cancer cells. 相似文献
22.
层状富锂材料具有超过250 mAh∙g−1的高可逆比容量,被认为是下一代高比能锂离子电池最具商业化前景的正极材料之一。然而,层状富锂材料在实际应用之前仍需解决诸多挑战,如高电压氧释放、层状到岩盐相的结构变化、过渡金属离子迁移等结构劣化,并由此带来了较低的初始库伦效率、电压/容量的衰减以及循环寿命的不足。针对以上问题,进行层状富锂材料改性无疑是一种行之有效的方法。本综述全面介绍了层状富锂材料的结构、组分以及电化学性能,在此基础上对材料改性策略进行了系统阐述,详细介绍了体相掺杂、表面包覆、缺陷设计、离子交换和微结构调控等一系列改性策略的现状以及发展趋势,最终提出了高容量和长循环层状富锂材料和高比能锂离子电池的设计思路。 相似文献
23.
利用ALD制备了TiO2限域的Pd催化剂, 研究了限域空间内Pd纳米颗粒与TiO2的界面作用对1,4-丁炔二醇(BYD)加氢性能的影响. 相比于管外负载型催化剂, 限域催化剂在催化1,4-丁炔二醇选择性加氢反应中体现出非常高的催化活性和1,4-丁烯二醇的选择性. HR-TEM、 EDX-Mapping、 XRD、 XPS和H2-TPR表征说明, 限域体系中Pd-TiO2的界面相互作用强于传统TiO2表面负载型Pd催化剂, 这种强界面作用不仅能够提高BYD的加氢活性, 也可抑制半加氢产物1,4-丁烯二醇的异构化和深度加氢, 提高1,4-丁烯二醇的选择性, 而且限域结构也可阻止管内壁Pd纳米颗粒的脱落, 提高催化剂的稳定性. 相似文献
24.
Wen Chen Yuan Zhang Prof. Hai-Bo Yi Prof. Fenglin Wang Prof. Xia Chu Prof. Jian-Hui Jiang 《Angewandte Chemie (International ed. in English)》2023,62(17):e202300162
Type I photodynamic therapy (PDT) represents a promising treatment modality for tumors with intrinsic hypoxia. However, type I photosensitizers (PSs), especially ones with near infrared (NIR) absorption, are limited and their efficacy needs improvement via new targeting tactics. We develop a NIR type I PS by engineering acridinium derived donor-π-acceptor systems. The PS exhibits an exclusive type I PDT mechanism due to effective intersystem crossing and disfavored energy transfer to O2, and shows selective binding to G-quadruplexes (G4s) via hydrogen bonds identified by a molecular docking study. Moreover, it enables fluorogenic detection of G4s and efficient O2⋅− production in hypoxic conditions, leading to immunogenic cell death and substantial variations of gene expression in RNA sequencing. Our strategy demonstrates augmented antitumor immunity for effective ablation of immunogenic cold tumor, highlighting its potential of RNA-targeted type I PDT in precision cancer therapy. 相似文献
25.
Chunlin Xie Shengfang Liu Wenxu Zhang Huimin Ji Shengqi Chu Qi Zhang Yougen Tang Haiyan Wang 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304259
Rechargeable zinc metal batteries are promising for large-scale energy storage. However, their practical application is limited by harsh issues such as uncontrollable dendrite growth, low Coulombic efficiency, and poor temperature tolerance. Herein, a unique design strategy using γ-valerolactone-based electrolyte and nanocarbon-coated aluminum substrate was reported to solve the above problems. The electrolyte with extremely low freezing point and high thermal stability enables the symmetric cells with long cycle life over a wide temperature range (−50 °C to 80 °C) due to its ability to regulate zinc nucleation and preferential epitaxial growth. Besides, the nanocarbon-coated aluminum substrate can also promote a higher Coulombic efficiency over a wide temperature range in contrast to the low Coulombic efficiency of copper substrates with significant irreversible alloying reactions because this unique substrate with excellent chemical stabilization can homogenize the interfacial electron/ion distribution. The optimized zinc metal capacitors can operate stably under various temperature conditions (2000 cycles at 30 °C with 66 % depth of discharge and 1200 cycles at 80 °C with 50 % depth of discharge). This unique electrolyte and substrate design strategy achieves a robust zinc metal battery over a wide temperature range. 相似文献
26.
Shiwei Pan Fan Chen Yanyan Zhang Liang Shao Prof. Dr. Lingling Chu 《Angewandte Chemie (International ed. in English)》2023,62(31):e202305426
A Markovnikov-selective hydrodifluoromethylation of alkynes with BrCF2H via nickel catalysis is described. This protocol proceeds via a migratory insertion of nickel hydride to alkyne followed by a CF2H-coupling, enabling straightforward access to diverse branched CF2H-alkenes with high efficiency and exclusive regioselectivity. The mild condition applies to a wide array of aliphatic and aryl alkynes with good functional group compatibility. Mechanistic studies are presented to support the proposed pathway. 相似文献
27.
Dr. Fangping Ren Ji Xian Zhaowei Jia Zhichun Chen Hongjun Fu Prof. Dr. Rui Wang Prof. Dr. Wen-Dao Chu Prof. Dr. Xiaobo Pan Jincai Wu 《Angewandte Chemie (International ed. in English)》2023,62(44):e202306759
To synthesize high molecular weight poly(phenolic ester) via a living ring-opening polymerization (ROP) of cyclic phenolic ester monomers remains a critical challenge due to serious transesterification and back-biting reactions. Both phenolic ester bonds in monomer and polymer chains are highly active, and it is difficult so far to distinguish them. In this work, an unprecedented selectively bifunctional catalytic system of tetra-n-butylammonium chloride (TBACl) was discovered to mediate the syntheses of high molecular weight salicylic acid-based copolyesters via a living ROP of salicylate cyclic esters (for poly(salicylic methyl glycolide) (PSMG), Mn=361.8 kg/mol, Ð<1.30). Compared to previous catalysis systems, the side reactions were suppressed remarkably in this catalysis system because phenolic ester bond in monomer can be selectively cleaved over that in polymer chains during ROP progress. Mechanistic studies reveal that the halide anion and alkyl-quaternaryammonium cation work synergistically, where the alkyl-quaternaryammonium cation moiety interacts with the carbonyl group of substrates via non-classical hydrogen bonding. Moreover, these salicylic acid-based copolyesters can be recycled to dimeric monomer under solution condition, and can be recycled to original monomeric monomers without catalyst under sublimation condition. 相似文献
28.
Chieh-Ming Hung Chi-Lun Mai Chi-Chi Wu Bo-Han Chen Chih-Hsuan Lu Che-Chun Chu Meng-Chuan Wang Prof. Shang-Da Yang Prof. Hsieh-Chih Chen Prof. Chen-Yu Yeh Prof. Pi-Tai Chou 《Angewandte Chemie (International ed. in English)》2023,62(40):e202309831
Self-assembled monolayers (SAMs) offer the advantage of facile interfacial modification, leading to significant improvements in device performance. In this study, we report the design and synthesis of a new series of carboxylic acid-functionalized porphyrin derivatives, namely AC-1, AC-3, and AC-5, and present, for the first time, a strategy to exploit the large π-moiety of porphyrins as a backbone for interfacing the indium tin oxide (ITO) electrode and perovskite active layer in an inverted perovskite solar cell (PSC) configuration. The electron-rich nature of porphyrins facilitates hole transfer and the formation of SAMs, resulting in a dense surface that minimizes defects. Comprehensive spectroscopic and dynamic studies demonstrate that the double-anchored AC-3 and AC-5 enhance SAMs on ITO, passivate the perovskite layer, and function as conduits to facilitate hole transfer, thus significantly boosting the performance of PSCs. The champion inverted PSC employing AC-5 SAM achieves an impressive solar efficiency of 23.19 % with a high fill factor of 84.05 %. This work presents a novel molecular engineering strategy for functionalizing SAMs to tune the energy levels, molecular dipoles, packing orientations to achieve stable and efficient solar performance. Importantly, our comprehensive investigation has unraveled the associated mechanisms, offering valuable insights for future advancements in PSCs. 相似文献
29.
Prof. Chien-Wei Chu Amalia Rizki Fauziah Prof. Li-Hsien Yeh 《Angewandte Chemie (International ed. in English)》2023,62(26):e202303582
The design of ion-selective membranes is the key towards efficient reverse electrodialysis-based osmotic power conversion. The tradeoff between ion selectivity (output voltage) and ion permeability (output current) in existing porous membranes, however, limits the upgradation of power generation efficiency for practical applications. Thus, we provide the simple guidelines based on fundamentals of ion transport in nanofluidics for promoting osmotic power conversion. In addition, we discuss strategies for optimizing membrane performance through analysis of various material parameters in membrane design, such as pore size, surface charge, pore density, membrane thickness, ion pathway, pore order, and ionic diode effect. Lastly, a perspective on the future directions of membrane design to further maximize the efficiency of osmotic power conversion is outlined. 相似文献
30.
Wei Zong Haiqi Gao Yue Ouyang Kaibin Chu Hele Guo Leiqian Zhang Wei Zhang Ruwei Chen Yuhang Dai Fei Guo Jiexin Zhu Zhenfang Zhang Chumei Ye Dr. Yue-E. Miao Prof. Johan Hofkens Dr. Feili Lai Prof. Tianxi Liu 《Angewandte Chemie (International ed. in English)》2023,62(27):e202218122
Competition from hydrogen/oxygen evolution reactions and low solubility of N2 in aqueous systems limited the selectivity and activity on nitrogen fixation reaction. Herein, we design an aerobic-hydrophobic Janus structure by introducing fluorinated modification on porous carbon nanofibers embedded with partially carbonized iron heterojunctions (Fe3C/Fe@PCNF-F). The simulations prove that the Janus structure can keep the internal Fe3C/Fe@PCNF-F away from water infiltration and endow a N2 molecular-concentrating effect, suppressing the competing reactions and overcoming the mass-transfer limitations to build a robust “quasi-solid–gas” state micro-domain around the catalyst surface. In this proof-of-concept system, the Fe3C/Fe@PCNF-F exhibits excellent electrocatalytic performance for nitrogen fixation (NH3 yield rate up to 29.2 μg h−1 mg−1cat. and Faraday efficiency (FE) up to 27.8 % in nitrogen reduction reaction; NO3− yield rate up to 15.7 μg h−1 mg−1cat. and FE up to 3.4 % in nitrogen oxidation reaction). 相似文献