全文获取类型
收费全文 | 427篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
化学 | 226篇 |
晶体学 | 1篇 |
力学 | 13篇 |
数学 | 54篇 |
物理学 | 138篇 |
出版年
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 14篇 |
2012年 | 21篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 29篇 |
2007年 | 15篇 |
2006年 | 22篇 |
2005年 | 32篇 |
2004年 | 24篇 |
2003年 | 20篇 |
2002年 | 18篇 |
2001年 | 8篇 |
2000年 | 12篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 14篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1969年 | 1篇 |
1939年 | 2篇 |
1932年 | 1篇 |
1917年 | 1篇 |
排序方式: 共有432条查询结果,搜索用时 0 毫秒
81.
82.
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
83.
Françoise Fournier Suzanne Altenburger-Combrisson Nguyen Kim Cuong Jean-Jacques Basselier 《Tetrahedron》1979,35(22):2633-2637
The addition of tetracyanotehylene to 2H-pyrans 1 results in a mixture of two isomeric adducts 6. The thermal decomposition of the compounds 6 gives rise to both a small percentage of the retro Diels-Alder, and a new mode of evolution leading to a mixture of furans (E+Z) 7. A detailed interpretation of the 13C spectra of the compounds 7 was established by comparison with the 13C spectra of 2,5-diphenylfuran and trans-stilbene. The structure 7 is confirmed by chemical degradation. 相似文献
84.
85.
John J. F. Fournier 《Israel Journal of Mathematics》1974,18(2):157-166
It is shown that ifG is an infinite compact abelian group, thenL
p (G) has the upper majorant property only ifp is even orp=∞.
The research for this paper was partially supported by National Research Council of Canada Operating Grant A-4822. 相似文献
86.
M. A. Olmstead N. M. Amer S. Kohn D. Fournier A. C. Boccara 《Applied Physics A: Materials Science & Processing》1983,32(3):141-154
We present a sensitive technique for determining the optical and thermal properties of solids, surfaces and thin films. This technique, photothermal displacement Spectroscopy, is based on the detection of the thermal expansion of a sample upon absorption of electromagnetic radiation. The technique is well suited for in situ ultrahigh vacuum studies and for experiments where wide temperature ranges are required. We show that surface and bulk optical absorption can be distinguished and that surface absorptions of αL=10?6/W of incident power can be measured. The theoretical basis of the signal generation is given, and excellent experimental and theoretical agreement is demonstrated. The implications of our findings to imaging and microscopy are discussed. 相似文献
87.
On the Uniqueness for the Spatially Homogeneous Boltzmann Equation with a Strong Angular Singularity
We prove an inequality on the Wasserstein distance with quadratic cost between two solutions of the spatially homogeneous
Boltzmann equation without angular cutoff, from which we deduce some uniqueness results. In particular, we obtain a local
(in time) well-posedness result in the case of (possibly very) soft potentials. A global well-posedness result is shown for
all regularized hard and soft potentials without angular cutoff. Our uniqueness result seems to be the first one applying
to a strong angular singularity, except in the special case of Maxwell molecules.
Our proof relies on the ideas of Tanaka (Z. Wahrscheinlichkeitstheor. Verwandte. Geb. 46(1):67–105, [1978]) we give a probabilistic interpretation of the Boltzmann equation in terms of a stochastic process. Then we show how to
couple two such processes started with two different initial conditions, in such a way that they almost surely remain close
to each other. 相似文献
88.
Manuela Chiper David Fournier Richard Hoogenboom Ulrich S. Schubert 《Macromolecular rapid communications》2008,29(20):1640-1647
Metallo‐supramolecular polymers offer attractive possibilities to combine the properties of polymers with the characteristics offered by the metal–ligand coordination. Here we present for the first time the combination of metal‐bis(terpyridine) complexes and lower critical solution temperature (LCST) polymers that can be switched by addressing either the thermosensitive polymer or the metal complex. We describe a new strategy for the synthesis of poly(N‐isopropylacrylamide) (PNIPAM) end functionalized with a terpyridine moiety, which is further used for the preparation of FeII and ZnII‐bis(terpyridine PNIPAM). The comparison of the LCST behavior of the uncomplexed ligands and their metal complexes that bear different counter ions is included. Furthermore, the switchability of the synthesized FeII system is demonstrated by a decomplexation reaction followed by the characterization of the uncomplexed ligand.
89.
Density functional theory was applied to a series of 13-atom Zn–Cu alloy clusters. We did a thorough search for the low-energy isomers by global optimization, plus explicit optimization of all homotops of the icosahedron. Structures of copper rich clusters tend to be compact, often icosahedra, whereas zinc rich clusters ( ${{\rm Zn}_8{\rm Cu}_{5}^{+}}$ , Zn9Cu4, Zn11Cu2) have compact copper cores surrounded by an incomplete shell of solvating Zn atoms. The icosahedral structure, low total energy, and large hardness of Zn7Cu6 indicate that it has special stability among Zn x Cu y clusters. However, Zn7Cu6 has many low lying isomers and a small cohesive energy compared to brass, which suggest that it is not stable in a broader sense. 相似文献
90.
The Suzuki-Miyaura (SM) cross-coupling reaction has recently become one of the most efficient methods for C-C bond construction opening a wide range of opportunities in organic synthesis. This study focused on the evaluation of the use of the SM reaction to modify peptides using a solid-phase synthesis approach, an avenue that was still not investigated intensively. We used as a peptide model [Ala (1,2,3), Leu (8)]Enk linked to a polystyrene support on which it was previously assembled. The aromatic residues Tyr (4) and Phe (7) of [Ala (1,2,3), Leu (8)]Enk were respectively substituted with p-iodo-Phe, and an SM-related strategy was developed. Results indicated that the reaction conditions involving K 3PO 4 or Na 2CO 3 (base), DMF (solvent), Pd(PPh 3) 4 (catalyst), and temperatures ranging from 50 to 80 degrees C during 20 h were found as optimal. Finally applying those optimal conditions, a series of [Ala (1,2,3), Leu (8)]Enk analogs modified at Tyr (4) or Phe (7) positions was synthesized using diverse boronic acid derivatives. 相似文献