全文获取类型
收费全文 | 1147篇 |
免费 | 63篇 |
国内免费 | 6篇 |
专业分类
化学 | 755篇 |
晶体学 | 7篇 |
力学 | 32篇 |
数学 | 190篇 |
物理学 | 232篇 |
出版年
2023年 | 9篇 |
2022年 | 14篇 |
2021年 | 26篇 |
2020年 | 33篇 |
2019年 | 36篇 |
2018年 | 25篇 |
2017年 | 14篇 |
2016年 | 37篇 |
2015年 | 46篇 |
2014年 | 45篇 |
2013年 | 65篇 |
2012年 | 94篇 |
2011年 | 111篇 |
2010年 | 57篇 |
2009年 | 51篇 |
2008年 | 88篇 |
2007年 | 72篇 |
2006年 | 57篇 |
2005年 | 48篇 |
2004年 | 40篇 |
2003年 | 28篇 |
2002年 | 22篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 7篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1971年 | 4篇 |
1969年 | 5篇 |
排序方式: 共有1216条查询结果,搜索用时 15 毫秒
121.
Clair S Ourdjini O Abel M Porte L 《Chemical communications (Cambridge, England)》2011,47(28):8028-8030
Control on the formation of a two-dimensional polymer could be achieved in two different ways. Manipulation with the tip of a scanning tunneling microscope allowed for assigning the localization of the polymerization reaction. Additionally, electron irradiation could accelerate greatly the reaction kinetics. 相似文献
122.
Dubacheva GV Galibert M Coche-Guerente L Dumy P Boturyn D Labbé P 《Chemical communications (Cambridge, England)》2011,47(12):3565-3567
Soft attachment of streptavidin to β-cyclodextrin-modified pegylated SAMs was efficiently performed in a reversible and repetitive way via orthogonal bifunctional linkers involving streptavidin-biotin recognition and redox-driven multivalent host-guest (β-cyclodextrin-ferrocene) interactions. 相似文献
123.
124.
Sjöqvist J Linares M Lindgren M Norman P 《Physical chemistry chemical physics : PCCP》2011,13(39):17532-17542
CHARMM force field parameter values for a class of oligothiophene derivatives have been derived with reference to density functional theory/B3LYP potential energy surfaces. The force field parametrization of these luminescent conjugated polyelectrolytes includes the electronic ground state as well as the strongly light absorbing first excited state. In conjunction with quantum chemical response theory calculations of transition state properties, a molecular dynamical model of the Stokes shift is obtained. The theoretical model is benchmarked against experimental data recorded at room temperature which refer to sodium salts of p-HTAA and p-FTAA with distilled water as a solvent. For p-HTAA the theoretically predicted Stokes shift of 112 nm is in good agreement with the experimental result of 124 nm, given the approximations about exciton localization that were introduced to obtain a force field for the excited state. 相似文献
125.
Berionni G Gonçalves AM Mathieu C Devic T Etchéberry A Goumont R 《Physical chemistry chemical physics : PCCP》2011,13(7):2857-2869
Nitro Benzoxadiazoles (benzofurazans), benzoxadiazoles-N-oxide (benzofuroxans) and benzothiadiazoles are ranked amongst the strongest electrophiles known to date. In the past twenty years, their propensity to act as electron organic acceptors has been less studied. In this paper, we report on the study of their electrochemical behavior and on the structural characterization of charge transfer complexes (CTC) deriving from their interaction with tetrathiafulvalene (TTF) derivatives, both in solution and in the solid state. The first half wave reduction potentials (E(1/2)(I)) associated with a reversible monoelectronic transfer process of a large set of nitro substituted benzoxadiazoles (benzofurazans), benzoxadiazoles-N-oxide (benzofuroxans) and benzothiadiazoles have been determined through a detailed electrochemical approach in acetonitrile with a microelectrode network using the ferrocene as an internal reference potential in this electrochemical study. Determination of the electron affinity (EA(CT)) of this series of substituted electrodeficient heteroaromatics as well as their LUMO energy was performed using the Charge Transfer Spectroscopic (CTS) method in solution and by DFT calculations, respectively. The use of the correlation EA(CT) versus the reversible half wave potential (E(1/2)(I)) appears to be a useful tool to estimate readily the E(1/2)(I) or EA(CT) values when they cannot be experimentally determined. The diffusion coefficient of these electrophiles has, for the first time, been determined in acetonitrile. These air stable electrodeficient heteroaromatics have been explored as potential new organic acceptors in the formation of charge transfer (CT) complexes with TTF derivatives. Crystallographic data of two CT complexes with TTF (especially the C-C and C-S bond lengths of the TTF moieties) indicate that these complexes exhibit weak electron delocalization and that both molecules remain neutral. Their resulting levels of charge transfer were probed using UV-visible, IR spectroscopy and by DFT calculations. 相似文献
126.
127.
de Langlard Mathieu Lamadie Fabrice Charton Sophie Debayle Johan 《Methodology and Computing in Applied Probability》2021,23(2):549-567
Methodology and Computing in Applied Probability - The paper focuses on a new method for the inference of a parametric random spheroid from the observations of its 2D orthogonal projections. Such a... 相似文献
128.
In the present study, we investigated the polymorphism and its time-dependence of a new series of bolaamphiphile molecules based on N-(12-Betainylamino-dodecane)-octyl β-D-Glucofuranosiduronamide Chloride. To obtain six members of this series, the length of the main bridging chain and the lateral chain were varied in order to modify the hydrophilic–lipophilic balance. Another chemical modification was to introduce a diacetylenic unit in the middle of the bridging chain to study the influence of the π–π stacking on the supramolecular organization of these molecules. Dry bolaamphiphiles self-organize in supramolecular structures such as lamellar crystalline structure, Lc; lamellar gel structure, Lβ′; lamellar fluid structure, Lα; and lamellar isotropic structure, L. Thermal hysteresis of these structures, following phase transitions, are investigated by small-angle and wide-angle X-ray scattering. Once the thermal cycle is accomplished, the system remains in the kinetically stabilized undercooled high-temperature phase at the temperature of 20°C. Subsequently, the time-dependence of the relaxation to the thermodynamically stable phase is followed, and very slow relaxation for a period on the order of hours or days is observed. The study of the polymorphism and the stability of various phases of this new series of bolaamphiphiles—which are issued from natural primary resources (sugar beet and wheat) and thus interesting for potential application in pharmaceutical, cosmetics, or food industry—was undertaken in this work. 相似文献
129.
Mathieu Gourcy 《Annales de l'Institut Henri Poincaré (B) Probabilités et Statistiques》2007,43(4):441
In this paper we obtain a Large Deviation Principle for the occupation measure of the solution to a stochastic Burgers equation which describes the exact rate of exponential convergence. This Markov process is strongly Feller and has a unique invariant measure. Moreover, the rate function is explicit: it is the level-2 entropy of Donsker-Varadhan. 相似文献
130.
P. Mathieu 《Probability Theory and Related Fields》1995,102(1):83-103
Summary We proveL
p> majorations for the suprema of the intersection local time of two planar Brownian motions. We deduce a sufficient condition on the correlation of two Brownian motions for their i.l.t. to be continuous.
Inegalités Barlow-Yor pour les temps locaux d'intersection de deux mouvements Browniens plans
Résumé On prouve des majorations en normeL p pour le suprema des temps locaux d'intersection de deux mouvements browniens plans, renormalisés ou non. On en déduit une condition suffisante sur la corrélation entre deux browniens pour que leur t.l.i. soient continus.相似文献