全文获取类型
收费全文 | 482篇 |
免费 | 29篇 |
专业分类
化学 | 388篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 36篇 |
物理学 | 81篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 13篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 15篇 |
2014年 | 14篇 |
2013年 | 43篇 |
2012年 | 27篇 |
2011年 | 21篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 28篇 |
2007年 | 21篇 |
2006年 | 28篇 |
2005年 | 17篇 |
2004年 | 23篇 |
2003年 | 27篇 |
2002年 | 23篇 |
2001年 | 8篇 |
2000年 | 16篇 |
1999年 | 12篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1943年 | 1篇 |
1938年 | 1篇 |
1936年 | 1篇 |
1912年 | 1篇 |
排序方式: 共有511条查询结果,搜索用时 46 毫秒
131.
Herman Gershon Donald D. Clarke John J. McMahon Muriel Gershon 《Monatshefte für Chemie / Chemical Monthly》2001,132(7):833-838
Summary. 2,5-, 3,5-, 3,6-, 3,7-, 4,5-, 5,6-, 5,7-, and 6,7-dibromo-8-quinolinols were prepared and tested against six fungi (Aspergillus niger, Aspergillus oryzae, Myrothecium verrucaria, Trichoderma viride, Mucor cirinelloides, and Trichophyton mentagrophytes) in Sabouraud dextrose broth. Most of the compounds were strongly antifungal, inhibiting five of the fungi below 1μg/cm3, but were somewhat less fungitoxic than the corresponding chloro analogues. M. cirinelloides was not inhibited by any of the compounds except 4,5-dibromo-8-quinolinol. This high level of fungitoxicity is attributed
to intramolecular synergism.
Received December 28, 2000. Accepted (revised) February 3, 2001 相似文献
132.
Muriel Hissler Anthony Harriman Pierre Jost Georges Wipff Raymond Ziessel 《Angewandte Chemie (International ed. in English)》1998,37(23):3249-3252
Binding of K + or Ba 2+ ions attenuates intramolecular electron transfer between a chromophore and an electron-affinic macrocyclic receptor (see schematic representation), and simultaneously amplifies luminescence. In the complexed state, photons absorbed by the dicationic chromophore are emitted as luminescence, whereas illumination of the uncomplexed superstructure causes rapid reduction of the receptor. 相似文献
133.
134.
Jean-Pierre Bouanich Ghislain Blanquet Muriel Lepère 《Journal of Molecular Spectroscopy》2004,227(2):172-179
H2-broadening coefficients have been measured for 35 lines of C2H4 at 173.2 K in the P, Q, and R branches of the ν7 fundamental band near 10 μm, using a tunable diode-laser spectrometer. These lines were individually fitted with a Voigt and a Rautian profile to determine their collisional widths. The resulting broadening coefficients, as well as those previously measured at room temperature are compared with values calculated on the basis of a semiclassical model of interacting linear molecules, using an atom-atom Lennard-Jones potential in addition to the weak electrostatic contributions. A satisfactory agreement is obtained for the results at room temperature, but the theoretical results at low temperature are generally smaller than the experimental data. Finally, the temperature dependence of the broadening coefficients has been determined both experimentally and theoretically. 相似文献
135.
In this paper we propose the application of double cavity fiber resonators as timing extraction circuits for gigabit networks. Spectral properties of double cavity fiber resonators, including the spectral enhancement achieved by means of the vemier effectare outlined. We investigate their suitability to obtain low cost all-fiber timing extraction circuits in broadband optical networks where single cavity structures previouslyproposed in the literature cannot be efficiently applied. 相似文献
136.
Muriel Ney-Nifle Marc Gabay 《Physica C: Superconductivity and its Applications》1995,250(3-4):349-360
We study the thermal fluctuations of anisotropic order parameters (OP) in layered superconductors. In particular, for copper oxides and a d-wave OP, we present some experimental consequences of fluctuations in the direction normal to the layers. It is shown that the c-axis penetration depth λc can have a “disorder-like” quadratic temperature dependence at low temperature. The fluctuations are analyzed in the framework of a Lawrence-Doniach model with an isotropic Fermi surface. Anisotropies pin the orientation of the OP to the crystallographic axes of the lattice. Then we study an extended t-J model that fits Fermi surface data of bilayers YBCO and BSCCO. This leads to a d-wave OP with two possible orientations and, including the thermal fluctuations, yields the announced temperature dependence of λc. Furthermore a reservoir layer is introduced. It implies a finite density of states at the Fermi energy which is successfully compared to conductance and specific heat measurements. 相似文献
137.
138.
Bachir Bentria Djamal Benbertal Zoulikha Hebboul Muriel Bagieu‐Beucher Alain Mosset 《无机化学与普通化学杂志》2005,631(5):894-901
The investigation of CdCl2‐HIO3 system, in aqueous and HNO3 solutions, revealed that anhydrous cadmium iodate presents a marked polymorphism. No less than four new Cd(IO3)2polymorphs have been isolated and characterized, two of which showing second harmonic generation activity. Single crystals of ε‐Cd(IO3)2 are obtained by slowly evaporating, at 60 °C, a saturated solution of γ‐Cd(IO3)2 in 30 % nitric acid. This compound crystallizes in the orthorhombic space group Pca21 [a = 17.581(2), b = 5.495(2), c = 11.163(2) Å]. The basic structural unit can be described as the connection of two cadmium polyhedrons with a short metal – metal distance of 3.88Å. These units are further linked through two other iodate bridges resulting in layers parallel to the (100) plane. The 3D linkage is ensured by short bonds of the fourth iodate group. 相似文献
139.
Bourgeois ME Wajer FT Roth M Briguet A Décorps M van Ormondt D Segebarth C Graveron-Demilly D 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2003,163(2):277-287
This paper analyzes the effects of intra-scan motion and demonstrates the possibility of correcting them directly in k-space with a new automatic retrospective method. The method is presented for series of 2D acquisitions with Cartesian sampling. Using a reference k-space acquisition (corrected for translations) within the series, intra-scan motion parameters are accurately estimated for each trajectory in k-space of each data set in the series resulting in pseudo-random sample positions. The images are reconstructed with a Bayesian estimator that can handle sparse arbitrary sampling in k-space and reduces intra-scan rotation artefacts to the noise level. The method has been assessed by means of a Monte Carlo study on axial brain images for different signal-to-noise ratios. The accuracy of motion estimates is better than 0.1 degrees for rotation, and 0.1 and 0.05 pixel, respectively, for translation along the read and phase directions for signal-to-noise ratios higher than 6 of the signals on each trajectory. An example of reconstruction from experimental data corrupted by head motion is also given. 相似文献
140.
Ohne Zusammenfassung 相似文献