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21.
Dr. Szymon Chorazy Tomasz Charytanowicz Dr. Dawid Pinkowicz Junhao Wang Dr. Koji Nakabayashi Stephen Klimke Prof. Dr. Franz Renz Prof. Dr. Shin-ichi Ohkoshi Prof. Dr. Barbara Sieklucka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15871-15879
A two-step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3-CNpy)2][Re(CN)8]}⋅H2O ( 1 ) (3-CNpy=3-cyanopyridine) assembly consisting of cyanido-bridged FeII-ReV square grid sheets bonded by Cs+ ions. The presence of two non-equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non-covalent interlayer interactions involving Cs+, [ReV(CN)8]3− ions, and 3-CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin-transition phenomenon could be tuned by an external pressure giving the room-temperature range of SCO, as well as by visible-light irradiation, inducing an efficient recovery of the high-spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect. 相似文献
22.
Herein we report a study of highly efficient platinum‐catalyzed hydrosilylation of dialkenylgermanes with silsesquioxanes and spherosilicates. The use of divinyl‐ and diallylgermanes allowed the synthesis of new classes of compounds, i. e., dumbbell‐type systems, silsesquioxanes with alkenyl pendant group, and oligomeric derivatives. The results are supported by detailed data from in situ FT‐IR and NMR measurements, enabling precise monitoring of the reaction progress and determination of regioselectivity of the formed products. 相似文献
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Aleksandra Bocian Adam Gorczyski Dawid Marcinkowski Grzegorz Dutkiewicz Violetta Patroniak Maciej Kubicki 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(4):367-374
The intermolecular interactions in the structures of a series of Schiff base ligands have been thoroughly studied. These ligands can be obtained in different forms, namely, as the free base 2‐[(2E)‐2‐(1H‐imidazol‐4‐ylmethylidene)‐1‐methylhydrazinyl]pyridine, C10H11N5, 1 , the hydrates 2‐[(2E)‐2‐(1H‐imidazol‐2‐ylmethylidene)‐1‐methylhydrazinyl]‐1H‐benzimidazole monohydrate, C12H12N6·H2O, 2 , and 2‐{(2E)‐1‐methyl‐2‐[(1‐methyl‐1H‐imidazol‐2‐yl)methylidene]hydrazinyl}‐1H‐benzimidazole 1.25‐hydrate, C13H14N6·1.25H2O, 3 , the monocationic hydrate 5‐{(1E)‐[2‐(1H‐1,3‐benzodiazol‐2‐yl)‐2‐methylhydrazinylidene]methyl}‐1H‐imidazol‐3‐ium trifluoromethanesulfonate monohydrate, C12H13N6+·CF3O3S?·H2O, 5 , and the dicationic 2‐{(2E)‐1‐methyl‐2‐[(1H‐imidazol‐3‐ium‐2‐yl)methylidene]hydrazinyl}pyridinium bis(trifluoromethanesulfonate), C10H13N52+·2CF3O3S?, 6 . The connection between the forms and the preferred intermolecular interactions is described and further studied by means of the calculation of the interaction energies between the neutral and charged components of the crystal structures. These studies show that, in general, the most important contribution to the stabilization energy of the crystal is provided by π–π interactions, especially between charged ligands, while the details of the crystal architecture are influenced by directional interactions, especially relatively strong hydrogen bonds. In one of the structures, a very interesting example of the nontypical F…O interaction was found and its length, 2.859 (2) Å, is one of the shortest ever reported. 相似文献
24.
Dawid Lichosyt Dr. Paweł Dydio Prof. Janusz Jurczak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17673-17680
Herein we report the synthesis and detailed studies of the anion‐binding properties of two 20‐membered macrocyclic tetramide receptors: one symmetrical, containing two identical azulene‐based bisamide units, the other a hybrid, containing a dipicolinic bisamide unit and an azulene‐based bisamide unit. Analysis of the crystal structures of the macrocyclic receptors revealed their preference for adopting similar well‐preorganized bent‐sheet conformations, both as free receptors and in their complexes with anions. Studies of the optical properties of both receptors revealed abilities to selectively sense phosphate anions (H2PO4?, HP2O73?), allowing for naked‐eye detection of the presence of these guests in DMSO. Binding studies in solution confirmed that the receptors bind strongly to a series of anions even in highly demanding media, such as mixtures of DMSO with water or with methanol. Comparison of the anion affinity of linear analogues with that of the macrocyclic receptors evidenced the importance of macrocyclic topology. Quantitative analysis revealed that the macrocyclic receptors are selective for H2PO4? over other anions. The affinity to H2PO4? seen for the symmetrical receptor, containing two azulene‐based subunits, is much higher than for the hybrid macrocycle containing both the azulene‐based and pyridine‐derived subunits. This highlights that the azulene‐based building block serves efficiently as both a binding site and a structure‐preorganizing motif. 相似文献
25.
We prove that every topological dynamical system (X,T) has a zero-dimensional principal extension, i.e. a zero-dimensional extension (Y,S) such that for every S-invariant measure ν on Y the conditional entropy h(ν|X) is zero. This reduces the discussion of many entropy-related properties to the zero-dimensional case which gives access to the various useful tools of symbolic dynamics. 相似文献
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Donor–acceptor nonradiative energy transfer mediated by surface plasmons on ultrathin metallic films
Selected properties of donor–acceptor energy transfer in the presence of surface plasmon coupled emission (SPCE) on metallic nanofilms are demonstrated. These properties of surface plasmon mediated energy transfer (SPMET) are for the first time compared to those of traditional energy transfer (ET) based on the same donor–acceptor system. The presence of plasmons significantly accelerates energy transfer as revealed by the results of fluorescence intensity decay. In particular, the rise time of acceptor fluorescence intensity upon donor excitation is 10 times shorter in the presence of SPCE. It is also observed that contrary to ET the sensibilized acceptor emission in SPMET is totally linearly polarized. 相似文献
30.
Synthesis of Inorganic Structural Isomers By Diffusion‐Constrained Self‐Assembly of Designed Precursors: A Novel Type of Isomerism 下载免费PDF全文
Marco Esters Matti B. Alemayehu Zachary Jones Dr. N. T. Nguyen Dr. Michael D. Anderson Corinna Grosse Prof. Saskia F. Fischer Prof. David C. Johnson 《Angewandte Chemie (International ed. in English)》2015,54(4):1130-1134
The structure of precursors is used to control the formation of six possible structural isomers that contain four structural units of PbSe and four structural units of NbSe2: [(PbSe)1.14]4[NbSe2]4, [(PbSe)1.14]3[NbSe2]3[(PbSe)1.14]1[NbSe2]1, [(PbSe)1.14]3[NbSe2]2[(PbSe)1.14]1[NbSe2]2, [(PbSe)1.14]2[NbSe2]3[(PbSe)1.14]2[NbSe2]1, [(PbSe)1.14]2[NbSe2]2[(PbSe)1.14]1[NbSe2]1[(PbSe)1.14]1[NbSe2]1, [(PbSe)1.14]2[NbSe2]1[(PbSe)1.14]1[NbSe2]2[(PbSe)1.14]1[NbSe2]1. The electrical properties of these compounds vary with the nanoarchitecture. For each pair of constituents, over 20 000 new compounds, each with a specific nanoarchitecture, are possible with the number of structural units equal to 10 or less. This provides opportunities to systematically correlate structure with properties and hence optimize performance. 相似文献