全文获取类型
收费全文 | 1453篇 |
免费 | 42篇 |
国内免费 | 9篇 |
专业分类
化学 | 958篇 |
晶体学 | 7篇 |
力学 | 22篇 |
数学 | 212篇 |
物理学 | 305篇 |
出版年
2023年 | 19篇 |
2022年 | 23篇 |
2021年 | 41篇 |
2020年 | 30篇 |
2019年 | 30篇 |
2018年 | 27篇 |
2017年 | 33篇 |
2016年 | 53篇 |
2015年 | 40篇 |
2014年 | 49篇 |
2013年 | 81篇 |
2012年 | 85篇 |
2011年 | 105篇 |
2010年 | 69篇 |
2009年 | 88篇 |
2008年 | 95篇 |
2007年 | 93篇 |
2006年 | 90篇 |
2005年 | 86篇 |
2004年 | 45篇 |
2003年 | 48篇 |
2002年 | 53篇 |
2001年 | 18篇 |
2000年 | 25篇 |
1999年 | 15篇 |
1998年 | 14篇 |
1997年 | 15篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有1504条查询结果,搜索用时 15 毫秒
991.
Ferran Gonzàlez de Rivera Dr. Inmaculada Angurell Dr. Marta D. Rossell Dr. Rolf Erni Dr. Jordi Llorca Núria J. Divins Prof. Guillermo Muller Dr. Miquel Seco Prof. Oriol Rossell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11963-11974
A facile strategy has been explored for loading noble metals onto the surface of ferrite nanoparticles with the assistance of phosphine‐functionalized linkers. Palladium loading is shown to occur with participation of both the phosphine function and the surface hydroxyl groups. Hybrid nanoparticles containing simultaneously Pd and Au (or Rh) are obtained by successive loading of metals. Similarly, ferrite nanoparticles decorated with Pd, Au, and Rh have also been formed by using the same strategy. The catalytic properties of the new nanoparticles are evidenced in processes such as reduction of 4‐nitrophenol or hydrogenation of styrene. Besides, the sequential process involving a cross‐coupling reaction followed by reduction of 1‐nitrobiphenyl has been successfully achieved by employing Pd/Au decorated nanoferrite particles. 相似文献
992.
Zhangyong Si Hui Wen Lim Moon Y. F. Tay Yu Du Lin Ruan Haofeng Qiu Rubí Zamudio‐Vazquez Sheethal Reghu Yahua Chen Wen Shuo Tiong Kalisvar Marimuthu Partha Pratim De Oon Tek Ng Yabin Zhu Yunn‐Hwen Gan Yonggui Robin Chi Hongwei Duan Guillermo C. Bazan E. Peter Greenberg Mary B. Chan‐Park Kevin Pethe 《Angewandte Chemie (International ed. in English)》2020,59(17):6819-6826
Carbapenem‐resistant Gram‐negative bacteria (GNB) are heading the list of pathogens for which antibiotics are the most critically needed. Many antibiotics are either unable to penetrate the outer‐membrane or are excluded by efflux mechanisms. Here, we report a cationic block β‐peptide (PAS8‐b‐PDM12) that reverses intrinsic antibiotic resistance in GNB by two distinct mechanisms of action. PAS8‐b‐PDM12 does not only compromise the integrity of the bacterial outer‐membrane, it also deactivates efflux pump systems by dissipating the transmembrane electrochemical potential. As a result, PAS8‐b‐PDM12 sensitizes carbapenem‐ and colistin‐resistant GNB to multiple antibiotics in vitro and in vivo. The β‐peptide allows the perfect alternation of cationic versus hydrophobic side chains, representing a significant improvement over previous antimicrobial α‐peptides sensitizing agents. Together, our results indicate that it is technically possible for a single adjuvant to reverse innate antibiotic resistance in all pathogenic GNB of the ESKAPE group, including those resistant to last resort antibiotics. 相似文献
993.
Giulia Morgese Bas F. M. de Waal Silvia Varela‐Aramburu Anja R. A. Palmans Lorenzo Albertazzi E. W. Meijer 《Angewandte Chemie (International ed. in English)》2020,59(39):17229-17233
Understanding cell/material interactions is essential to design functional cell‐responsive materials. While the scientific literature abounds with formulations of biomimetic materials, only a fraction of them focused on mechanisms of the molecular interactions between cells and material. To provide new knowledge on the strategies for materials/cell recognition and binding, supramolecular benzene‐1,3,5‐tricarboxamide copolymers bearing benzoxaborole moieties are anchored on the surface of human erythrocytes via benzoxaborole/sialic‐acid binding. This interaction based on both dynamic covalent and non‐covalent chemistries is visualized in real time by means of total internal reflection fluorescence microscopy. Exploiting this imaging method, we observe that the functional copolymers specifically interact with the cell surface. An optimal fiber affinity towards the cells as a function of benzoxaborole concentration demonstrates the crucial role of multivalency in these cell/material interactions. 相似文献
994.
Tim Möller Fabian Scholten Trung Ngo Thanh Ilya Sinev Janis Timoshenko Xingli Wang Zarko Jovanov Manuel Gliech Beatriz Roldan Cuenya Ana Sofia Varela Peter Strasser 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18130-18139
The direct electrochemical conversion of carbon dioxide (CO2) into multi-carbon (C2+) products still faces fundamental and technological challenges. While facet-controlled and oxide-derived Cu materials have been touted as promising catalysts, their stability has remained problematic and poorly understood. Herein we uncover changes in the chemical and morphological state of supported and unsupported Cu2O nanocubes during operation in low-current H-Cells and in high-current gas diffusion electrodes (GDEs) using neutral pH buffer conditions. While unsupported nanocubes achieved a sustained C2+ Faradaic efficiency of around 60 % for 40 h, the dispersion on a carbon support sharply shifted the selectivity pattern towards C1 products. Operando XAS and time-resolved electron microscopy revealed the degradation of the cubic shape and, in the presence of a carbon support, the formation of small Cu-seeds during the surprisingly slow reduction of bulk Cu2O. The initially (100)-rich facet structure has presumably no controlling role on the catalytic selectivity, whereas the oxide-derived generation of under-coordinated lattice defects, can support the high C2+ product yields. 相似文献
995.
Dr. Jeffrey I. Seeman Dr. Guillermo Restrepo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(8):2962-2981
Over the past several decades, the Nobel Prize program has slowly but steadily been modified in both transparent and opaque ways. A transparent change has been the creation of the Nobel Prize in Economic Sciences, officially known as the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel. An opaque change has been the mutation of the Nobel Prize in Chemistry into what is effectively the “Nobel Prize in Chemistry or Life Sciences.” This paper presents a detailed study of this opaque change, including evidence that the disciplines of chemistry and biochemistry cover, today, intellectually quite distinct and generally scientifically-unrelated intellectual territory. This paper supports the evolution of the Nobel Prizes, and encourages the Nobel Prize program to move from opaque to transparent change processes for the next generations of achievement in the sciences. 相似文献
996.
Translation of real solid spherical harmonics 总被引:1,自引:0,他引:1
Jaime Fernández Rico Rafael López Ignacio Ema Guillermo Ramírez 《International journal of quantum chemistry》2013,113(10):1544-1548
General formulae for the translation of both regular and irregular real solid harmonics are derived from the addition theorems of complex harmonics. The resultant expressions, being too complicated for practical purposes, are rewritten in a more compact and friendly manner. The usefulness of these simplified expressions is illustrated with two examples: the potential generated by sets of charges and multipoles in points placed far away, and the expansion in regular harmonics of the long‐range potential inside a region surrounded by pointwise charge distributions. © 2012 Wiley Periodicals, Inc. 相似文献
997.
Emilia M. Reyes-Gallardo Guillermo Lasarte-AragonésRafael Lucena Soledad CárdenasMiguel Valcárcel 《Journal of chromatography. A》2013,1271(1):50-55
In this article, the combination of commercial polymeric microparticles (OASIS MCX) and cobalt ferrite nanoparticles is evaluated in dispersive micro-solid phase extraction (D-μSPE) for the determination of six nitroaromatic hydrocarbons in water. The high affinity of the polymeric material toward the target analytes as well as the magnetic behavior of cobalt ferrite nanoparticles are combined in a synergic way to developed an efficient and simple D-μSPE approach. The sorptive performance of the hybrid material is compared with that most usual sorbents and the effect of its synthesis steps on the extraction capability is also evaluated in depth. After the optimization of selected variables, D-μSPE method was assessed in terms of linearity, sensitivity, precision and accuracy. The new extraction method allows the determination of the target compounds with limits of detection in the range from 0.12 to 1.26 μg/L and relative standard deviations lower than 9.6%. The recovery study was performed in two different water samples obtaining percentages from 71 to 103%, which demonstrated the applicability of the hybrid sorbent for the selected analytical problem. 相似文献
998.
Xiaofen Chen Dr. Xiaofeng Liu Mark A. Burgers Dr. Ye Huang Prof. Dr. Guillermo C. Bazan 《Angewandte Chemie (International ed. in English)》2014,53(52):14378-14381
High‐efficiency bulk heterojunction (BHJ) organic solar cells with power conversion efficiencies of more than 5 % can be fabricated using the green solvent 2‐MeTHF. The active layers comprise a blend of a molecular semiconductor donor with intermediate dimensions (X2) and the soluble fullerene derivative [6,6]‐phenyl‐C61‐butyricacidoctylester (PC61BC8). A switch of the processing solvent from chloroform to 2‐MeTHF leads to no negative impacts on the morphology and charge‐transport properties of optimally performing BHJ films. Examinations by absorption spectroscopy, atomic force microscopy, and grazing incidence wide‐angle X‐ray scattering reveal no significant modification of morphology. These results show that green solvents can be excellent alternatives for large‐area printing of high‐performance organic photovoltaics (OPVs) and thus open new opportunities for sustainable mass production of organic solar cells and other optoelectronic devices. 相似文献
999.
1000.
María Navarro-Pascual-Ahuir Rafael Lucena Soledad Cárdenas Guillermo Ramis-Ramos Miguel Valcárcel José Manuel Herrero-Martínez 《Analytical and bioanalytical chemistry》2014,406(25):6329-6336
The preparation of polymeric monoliths with embedded carboxy-modified single-walled carbon nanotubes (c-SWNTs) and their use for capillary electrochromatography (CEC) is described. Carbon nanotube composites were obtained by preparing a polymerization mixture in the presence of increasing c-SWNT concentrations, followed by UV initiation. The novel stationary phases were studied by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Using short UV-polymerization times, the optimized porogenic solvent (a binary mixture of 1,4-butanediol and 2-propanol) gave rise to polymeric beds with homogenously dispersed embedded c-SWNTs. The CEC features of these monoliths were evaluated using polycyclic aromatic hydrocarbons (PAHs), non-steroidal anti-inflammatory drugs (NSAIDs) and chiral compounds. The monolith prepared in the presence of c-SWNTs showed enhanced resolution of the text mixtures, including a remarkable capability to separate enantiomers. Graphical Abstract
UV-polymerized polymeric monoliths with embedded c-SWNTs for CEC applications 相似文献