全文获取类型
收费全文 | 274篇 |
免费 | 25篇 |
专业分类
化学 | 187篇 |
力学 | 8篇 |
数学 | 35篇 |
物理学 | 69篇 |
出版年
2023年 | 8篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 19篇 |
2019年 | 16篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 15篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 15篇 |
2012年 | 23篇 |
2011年 | 19篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1998年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有299条查询结果,搜索用时 421 毫秒
91.
Dr. Marta Dal Molin Quentin Verolet Saeideh Soleimanpour Prof. Stefan Matile 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6012-6021
This article assembles pertinent insights behind the concept of planarizable push–pull probes. As a response to the planarization of their polarized ground state, a red shift of their excitation maximum is expected to report on either the disorder, the tension, or the potential of biomembranes. The combination of chromophore planarization and polarization contributes to various, usually more complex processes in nature. Examples include the color change of crabs or lobsters during cooking or the chemistry of vision, particularly color vision. The summary of lessons from nature is followed by an overview of mechanosensitive organic materials. Although often twisted and sometimes also polarized, their change of color under pressure usually originates from changes in their crystal packing. Intriguing exceptions include the planarization of several elegantly twisted phenylethynyl oligomers and polymers. Also mechanosensitive probes in plastics usually respond to stretching by disassembly. True ground‐state planarization in response to molecular recognition is best exemplified with the binding of thoughtfully twisted cationic polythiophenes to single‐ and double‐stranded oligonucleotides. Molecular rotors, en vogue as viscosity sensors in cells, operate by deplanarization of the first excited state. Pertinent recent examples are described, focusing on λ‐ratiometry and intracellular targeting. Complementary to planarization of the ground state with twisted push–pull probes, molecular rotors report on environmental changes with quenching or shifts in emission rather than absorption. The labeling of mechanosensitive channels is discussed as a bioengineering approach to bypass the challenge to create molecular mechanosensitivity and use biological systems instead to sense membrane tension. With planarizable push–pull probes, this challenge is met not with twistome screening, but with “fluorescent flippers,” a new concept to insert large and bright monomers into oligomeric probes to really feel the environment and also shine when twisted out of conjugation. 相似文献
92.
Dr. Quentin Benito Dr. Isabelle Maurin Thibaut Cheisson Dr. Gregory Nocton Dr. Alexandre Fargues Dr. Alain Garcia Dr. Charlotte Martineau Dr. Thierry Gacoin Prof. Jean‐Pierre Boilot Dr. Sandrine Perruchas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5892-5897
Luminescent mechanochromic materials are particularly appealing for the development of stimuli‐responsive materials. Establishing the mechanism responsible for the mechanochromism is always an issue owing to the difficulty in characterizing the ground phase. Herein, the study of real crystalline polymorphs of a mechanochromic and thermochromic luminescent copper iodide cluster permits us to clearly establish the mechanism involved. The local disruption of the crystal packing induces changes in the cluster geometry and in particular the modification of the cuprophilic interactions, which consequently modify the emissive states. This study constitutes a step further toward the understanding of the mechanism involved in the mechanochromic luminescent properties of multimetallic coordination complexes. 相似文献
93.
Quentin Brouette 《Archive for Mathematical Logic》2017,56(1-2):119-129
We study definable types in the theory of closed ordered differential fields (CODF). We show a condition for a type to be definable, then we prove that definable types are dense in the Stone space of CODF. 相似文献
94.
95.
Time‐of‐flight secondary ion mass spectrometry imaging of biological samples with delayed extraction for high mass and high spatial resolutions 下载免费PDF全文
96.
Dr. Quentin Simon Dr. Davide Barreca Dr. Alberto Gasparotto Dr. Chiara Maccato Prof. Eugenio Tondello Dr. Cinzia Sada Dr. Elisabetta Comini Prof. Giorgio Sberveglieri Dr. Manish Banerjee Dr. Ke Xu Prof. Anjana Devi Prof. Roland A. Fischer 《Chemphyschem》2012,13(9):2342-2348
CuO/ZnO nanocomposites were synthesized on Al2O3 substrates by a hybrid plasma‐assisted approach, combining the initial growth of ZnO columnar arrays by plasma‐enhanced chemical vapor deposition (PE‐CVD) and subsequent radio frequency (RF) sputtering of copper, followed by final annealing in air. Chemical, morphological, and structural analyses revealed the formation of high‐purity nanosystems, characterized by a controllable dispersion of CuO particles into ZnO matrices. The high surface‐to‐volume ratio of the obtained materials, along with intimate CuO/ZnO intermixing, resulted in the efficient detection of various oxidizing and reducing gases (such as O3, CH3CH2OH, and H2). The obtained data are critically discussed and interrelated with the chemical and physical properties of the nanocomposites. 相似文献
97.
Quentin Berger Francesco Caravenna Julien Poisat Rongfeng Sun Nikos Zygouras 《Communications in Mathematical Physics》2014,326(2):507-530
We study random pinning and copolymer models, when the return distribution of the underlying renewal process has a polynomial tail with finite mean. We compute the asymptotic behavior of the critical curves of the models in the weak coupling regime, showing that it is universal. This proves a conjecture of Bolthausen, den Hollander and Opoku for copolymer models (Bolthausen et al., in Ann Probab, 2012), which we also extend to pinning models. 相似文献
98.
We consider the question of finding deep cuts from a model with two rows of the type $P_I=\{(x,s)\in \mathbb{Z }^2\times \mathbb{R }^n_+ : x=f+Rs\}$ . To do that, we show how to reduce the complexity of setting up the polar of $\mathop {\mathrm{conv}}(P_I)$ from a quadratic number of integer hull computations to a linear number of integer hull computations. Furthermore, we present an algorithm that avoids computing all integer hulls. A polynomial running time is not guaranteed but computational results show that the algorithm runs quickly in practice. 相似文献
99.
Quentin Michaudel Guillaume Journot Alicia Regueiro‐Ren Animesh Goswami Zhiwei Guo Thomas P. Tully Lufeng Zou Raghunath O. Ramabhadran Kendall N. Houk Phil S. Baran 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(45):12287-12292
Physicochemical properties constitute a key factor for the success of a drug candidate. Whereas many strategies to improve the physicochemical properties of small heterocycle‐type leads exist, complex hydrocarbon skeletons are more challenging to derivatize because of the absence of functional groups. A variety of C H oxidation methods have been explored on the betulin skeleton to improve the solubility of this very bioactive, yet poorly water‐soluble, natural product. Capitalizing on the innate reactivity of the molecule, as well as the few molecular handles present on the core, allowed oxidations at different positions across the pentacyclic structure. Enzymatic oxidations afforded several orthogonal oxidations to chemical methods. Solubility measurements showed an enhancement for many of the synthesized compounds. 相似文献
100.
Eaves JM Summerfield AQ Kitterick PT 《The Journal of the Acoustical Society of America》2011,130(1):501-507
Previous studies have assessed the importance of temporal fine structure (TFS) for speech perception in noise by comparing the performance of normal-hearing listeners in two conditions. In one condition, the stimuli have useful information in both their temporal envelopes and their TFS. In the other condition, stimuli are vocoded and contain useful information only in their temporal envelopes. However, these studies have confounded differences in TFS with differences in the temporal envelope. The present study manipulated the analytic signal of stimuli to preserve the temporal envelope between conditions with different TFS. The inclusion of informative TFS improved speech-reception thresholds for sentences presented in steady and modulated noise, demonstrating that there are significant benefits of including informative TFS even when the temporal envelope is controlled. It is likely that the results of previous studies largely reflect the benefits of TFS, rather than uncontrolled effects of changes in the temporal envelope. 相似文献