全文获取类型
收费全文 | 706篇 |
免费 | 49篇 |
国内免费 | 4篇 |
专业分类
化学 | 571篇 |
晶体学 | 1篇 |
力学 | 24篇 |
数学 | 62篇 |
物理学 | 101篇 |
出版年
2024年 | 3篇 |
2023年 | 12篇 |
2022年 | 12篇 |
2021年 | 14篇 |
2020年 | 30篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 30篇 |
2015年 | 35篇 |
2014年 | 33篇 |
2013年 | 38篇 |
2012年 | 83篇 |
2011年 | 87篇 |
2010年 | 42篇 |
2009年 | 36篇 |
2008年 | 48篇 |
2007年 | 46篇 |
2006年 | 34篇 |
2005年 | 36篇 |
2004年 | 31篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1890年 | 2篇 |
排序方式: 共有759条查询结果,搜索用时 15 毫秒
101.
A. Blaise J.M. Fournier D. Damien A. Wojakowski J.P. Charvillat 《Journal of magnetism and magnetic materials》1982,30(2):265-268
The magnetic properties of a collection of single crystals of NpAs2 have been investigated in the temperature range 4.2-300 K and in applied fields up to 100 kOe. For small magnetic fields (3 kOe), NpAs2 is ferromagnetic up to TIC=18 K, antiferromagnetic from 28 K to TN=52 K, then paramagnetic. Both transitions are first order. When the applied field increases TIC is shifted towards TN. The antiferromagnetic phase disappears for H#62;30 kOe. The ferromagnetic range is characterized by a very large anisotropy. In the paramagnetic state, NpAs2 has an effective moment 1.88 μB. 相似文献
102.
Dietrich-Buchecker C Colasson B Jouvenot D Sauvage JP 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(15):4374-4386
The synthesis of two multisite ligands containing four and five 1,10-phenanthroline (phen) chelates in line, respectively, is presented. The connectors are 1,3-phenylene linkers. The two ligands were prepared following multistep procedures, the two key reactions being the Suzuki coupling reaction between aromatic nuclei and the nucleophilic addition of aryllithium derivatives onto a phen fragment. The coordination chemistry of both ligands with Li+ ions was very clean and selective, whereas their reaction with copper(I) led to intractable mixtures of insoluble complexes. The tetraphen and the pentaphen compounds afforded almost quantitatively the four- and five-lithium double-stranded helical complexes, respectively. The helical systems are probably highly wound, as indicated by NMR measurements. The pronounced strain of the 5-Li+ complex is reflected by the easy loss of a lithium cation, as shown by electrospray mass spectrometry. 相似文献
103.
For each , we construct an uncountable family of free ergodic measure preserving actions of the free group on the standard probability space such that any two are nonorbit equivalent (in fact, not even stably orbit equivalent). These actions are all ``rigid' (in the sense of Popa), with the IIfactors mutually nonisomorphic (even nonstably isomorphic) and in the class
104.
Miao J Chen CC Song C Nishino Y Kohmura Y Ishikawa T Ramunno-Johnson D Lee TK Risbud SH 《Physical review letters》2006,97(21):215503
In combination of direct phase retrieval of coherent x-ray diffraction patterns with a novel tomographic reconstruction algorithm, we, for the first time, carried out quantitative 3D imaging of a heat-treated GaN particle with each voxel corresponding to 17 x 17 x 17 nm3. We observed the platelet structure of GaN and the formation of small islands on the surface of the platelets, and successfully captured the internal GaN-Ga2O3 core shell structure in three dimensions. This work opens the door for nondestructive and quantitative imaging of 3D morphology and 3D internal structure of a wide range of materials at the nanometer scale resolution that are amorphous or possess only short-range atomic organization. 相似文献
105.
Evi Vinck Damien M. Murphy Ian A. Fallis Sabine Van Doorslaer 《Applied magnetic resonance》2010,37(1-4):289-303
We recently demonstrated how the aerobic addition of acetic acid to N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-diamino CoII, [Co(1)], leads to the formation of an unusual coordinated CoIII-phenoxyl radical. In this work, some of the structural aspects associated with the Schiff-base-derived ligand (1) that are crucial for the acid-mediated formation of the phenoxyl radical are investigated. For comparison with [Co(1)], we therefore studied the influence of acetic acid on two complexes: (1) the N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-ethane-diamino CoII complex, [Co(2)], that lacks the cyclohexyl group of [Co(1)], and (2) the N′-disalicylidene-ethylenediamine CoII salen complex, [Co(3)], that lacks both the tertiary butyl groups and the cyclohexyl groups. It is shown that the cyclohexyl group of [Co(1)] is not involved in the formation or stabilization of the phenoxyl radical, whereas the tertiary butyl groups of [Co(1)] play a crucial role. In addition, the characteristics of the phenoxyl radical, formed after aerobic addition of acetic acid to [Co(2)], are analyzed in detail by pulsed electron paramagnetic resonance, in combination with isotopic labeling. The experimental data are compared to density functional theory computations and to previous data on the acid-mediated phenoxyl radical of [Co(1)]. 相似文献
106.
Damien Weidmann Chad B. Roller Clive Oppenheimer Alan Fried Frank K. Tittel 《Isotopes in environmental and health studies》2013,49(4):293-302
Recent developments of two mid-infrared tunable laser spectrometers dedicated to carbon isotope ratio determination are presented. First, a field deployable quantum cascade laser-based sensor is described, along with line selection strategy for 13/12CO2 ratio measurements. Secondly, an instrument architecture based on difference frequency generation is presented. The analyses of fundamental limitations, specifically temperature and pressure stability, and water vapor collision broadening, are detailed. 相似文献
107.
108.
109.
110.
Sylvain Sudan Damien W. Chen Cesare Berton Farzaneh Fadaei-Tirani Kay Severin 《Angewandte Chemie (International ed. in English)》2023,62(9):e202218072
A water-soluble coordination cage was obtained by reaction of Pd(NO3)2 with a 1,3-di(pyridin-3-yl)benzene ligand featuring a short PEG chain. The cavity of the metal-organic cage contains one nitrate anion, which is readily replaced by chloride. The apparent association constant for chloride binding in buffered aqueous solution is Ka=1.8(±0.1)×105 M−1. This value is significantly higher than what has been reported for other macrocyclic chloride receptors. The heavier halides Br− and I− compete with binding or self-assembly, but the receptor displays very good selectivity over common anions such as phosphate, acetate, carbonate, and sulfate. A further increase of the chloride binding affinity by a factor of 3 was achieved using a fluorinated dipyridyl ligand. 相似文献