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排序方式: 共有127条查询结果,搜索用时 46 毫秒
1.
Matsuda R Kitaura R Kitagawa S Kubota Y Kobayashi TC Horike S Takata M 《Journal of the American Chemical Society》2004,126(43):14063-14070
In situ synchrotron X-ray powder diffraction patterns of porous coordination polymers [[Cu(2)(pzdc)(2)(bpy)].G] have been measured (pzdc = pyrazine-2,3-dicarboxylate, bpy = 4,4'-bipyridine) (where G = H(2)O for CPL-2 superset H(2)()O, G = benzene for CPL-2 superset benzene, and G = void for the apohost). The structures of apohost and CPL-2 superset benzene were determined from Rietveld analysis. Adsorption of benzene in the channels induced a remarkable contraction in the crystal (b axis; 6.8%, volume; 4.9%), although the channels were occupied by the benzene molecules. This crystal transformation provides a new pore structure that is well suited for benzene molecules, and we denote it as a "shape-responsive fitting" transformation. This type of pore gives rise to a new guideline: frameworks can be composed of flexible motifs that are linked via strong bond and/or stiff motifs that are connected via weaker bonds. 相似文献
2.
The ruthenium-catalysed double addition of trimethylsilyldiazomethane to alkynes developed by Dixneuf and co-workers was applied to the synthesis of 2-alkyl- or 2-aryl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,4-bis(trimethylsilyl)-1,3-butadienes by use of alkynylboronates instead of alkynes. Di- and tetrasubstituted 1,3-butadienes were prepared from a 2-boryl-1,4-disilyl-1,3-butadiene, using the Suzuki-Miyaura coupling reaction, iodolysis of the alkenylsilane moieties with N-iodosuccinimide and hydrolysis of the carbon-silicon bonds with trifluoroacetic acid. The same compound was converted also to a bicyclic compound, a trisubstituted 1,3-butadiene and a dienone through the Diels-Alder reaction, oxidation of the alkenylboronate moiety and the Mukaiyama aldol reaction. 相似文献
3.
Kitaura R Iwahori F Matsuda R Kitagawa S Kubota Y Takata M Kobayashi TC 《Inorganic chemistry》2004,43(21):6522-6524
A new three-dimensional (3-D) jungle-gym-like open metal-organic framework has been synthesized from a two-dimensional (2-D) layer compound using a heterogeneous pillar insertion reaction. Both the starting 2-D layer and the resulting 3-D open compounds have been characterized using X-ray crystallography. 相似文献
4.
Let f : S(E) → S(B) be a surjective isometry between the unit spheres of two weakly compact JB*-triples not containing direct summands of rank less than or equal to 3. Suppose E has rank greater than or equal to 5. Applying techniques developed in JB*-triple theory, we prove that f admits an extension to a surjective real linear isometry T : E → B. Among the consequences, we show that every surjective isometry between the unit spheres of two compact C*-algebras A and B, without assuming any restriction on the rank of their direct summands(and in particular when A = K(H) and B = K(H′)), extends to a surjective real linear isometry from A into B. These results provide new examples of infinite-dimensional Banach spaces where Tingley's problem admits a positive answer. 相似文献
5.
Amine‐Responsive Adaptable Nanospaces: Fluorescent Porous Coordination Polymer for Molecular Recognition 下载免费PDF全文
Ritesh Haldar Prof. Ryotaro Matsuda Prof. Susumu Kitagawa Prof. Subi J. George Prof. Tapas Kumar Maji 《Angewandte Chemie (International ed. in English)》2014,53(44):11772-11777
Flexible and dynamic porous coordination polymers (PCPs) with well‐defined nanospaces composed of chromophoric organic linkers provide a scaffold for encapsulation of versatile guest molecules through noncovalent interactions. PCPs thus provide a potential platform for molecular recognition. Herein, we report a flexible 3D supramolecular framework {[Zn(ndc)(o‐phen)]?DMF}n (o‐phen=1,10‐phenanthroline, ndc=2,6‐napthalenedicarboxylate) with confined nanospaces that can accommodate different electron‐donating aromatic amine guests with selective turn‐on emission signaling. This system serves as a molecular recognition platform through an emission‐readout process. Such unprecedented tunable emission with different amines is attributed to its emissive charge‐transfer (CT) complexation with o‐phen linkers. In certain cases this CT emission is further amplified by energy transfer from the chromophoric linker unit ndc, as evidenced by single‐crystal X‐ray structural characterization. 相似文献
6.
We give a functional Korovkin-type theorem onB(X), the space of bounded complex-valued functions on an arbitrary setXand investigate a BKW-operator onB(X) for a finite collection of test functions with a suitable property and a seminorm defined by a finite subset ofX. 相似文献
7.
Shirakawa E Morita R Tsuchimoto T Kawakami Y 《Journal of the American Chemical Society》2004,126(42):13614-13615
Molecular hydrogen adds to aliphatic and aromatic alkynylstannanes in the presence of a ruthenium catalyst, pushing the stannyl group to the adjacent carbon atom to give alpha-substituted vinylstannanes. This is the first achievement of hydrogenation of alkynylstannanes, which is applicable also to the deuteration affording precursors for an important class of deuterium-labeled compounds. 相似文献
8.
9.
Ryotaro Tanaka 《Central European Journal of Mathematics》2014,12(11):1700-1713
The notion of the frame of the unit ball of Banach spaces was introduced to construct a new calculation method for the Dunkl-Williams constant. In this paper, we characterize the frame of the unit ball by using k-extreme points and extreme points of the unit ball of two-dimensional subspaces. Furthermore, we show that the frame of the unit ball is always closed, and is connected if the dimension of the space is not less than three. As infinite dimensional examples, the frame of the unit balls of c 0 and ? p are determined. 相似文献
10.
In order to resolve the long-standing issue of how itinerant ferromagnetism is affected by lattice structure and Hund's coupling, we compare various three-dimensional lattice structures in the single- and multiorbital Hubbard models with the dynamical mean-field theory with an improved quantum Monte Carlo algorithm that preserves the spin-SU(2) symmetry. The result indicates that both the lattice structure and the d-orbital degeneracy are essential for the ferromagnetism in the parameter region representing a transition metal. Specifically, (a) Hund's coupling, despite the common belief, is important, which is here identified to come from particle-hole scatterings, and (b) the ferromagnetism is a correlation effect (outside the Stoner picture) as indicated from the band-filling dependence. 相似文献