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71.
Ananias Sandra R. Mauro Antonio E. Zutin Katia Picchi Cristina M.C. Santos Regina H.A. 《Transition Metal Chemistry》2004,29(3):284-290
The cyanate-bridged cyclopalladated compound [Pd(N,C-dmba)(-NCO)]2
(1)(dmba = PhCH2NMe2) reacts in CH2Cl2 with 2,3-lutidine (2,3-lut), 3,4-lutidine (3,4-lut), 2,2-bipyridine (2,2-bipy) and 4,4-bipyridine (4,4-bipy), to give [Pd(N,C-dmba)(NCO)(2,3-lut)](2), [Pd(N,C-dmba)(NCO)(3,4-lut)](3), [{Pd(N,C-dmba)(NCO)}2(-2,2-bipy)]· CH2Cl2
(4) and [{Pd(N,C-dmba)(NCO)}2(-4,4-bipy)]· CH2Cl2
(5), respectively. The compounds were characterized by elemental analysis, i.r. and n.m.r. spectroscopy and also by t.g.a. The i.r. spectra of (2–5) display typical bands of monodentate N-bonded cyanate groups, whereas the n.m.r. data of (4) are consistent with the presence of a bridging 2,2-bipyridine ligand. Complex (4) decomposes slowly in acetone. One of the products formed, [Pd(H2CCOMe)Cl(2,2-bipy)](6), was characterized by X-ray diffraction. As inferred from the t.g.a., the thermal stability decreases in the order:[{Pd(N,C-dmba)(NCO)}2(-4,4-bipy)].CH2Cl2
(5) > [Pd(N,C-dmba)(2,3-lut)(NCO)](2)=[Pd(N,C-dmba)(3,4-lut)(NCO)](3) > [{Pd(N,C-dmba)(NCO)}2(-2,2-bipy)]· CH2Cl2
(4). According to thermal analysis and X-ray diffraction patterns compounds (2–3) decompose into metallic palladium Pd(0), whereas (4–5) decompose with the formation of PdO. The X-ray crystal and molecular structure of [Pd(N,C-dmba)(NCO)(2,3-lut)](2) was determined. The lutidine unit is perpendicular to the coordination plane. 相似文献
72.
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74.
Dr. Farah Benyettou Dr. Katia Nchimi‐Nono Dr. Mustapha Jouiad Dr. Yoann Lalatonne Dr. Irena Milosevic Prof. Laurence Motte Prof. John‐Carl Olsen Prof. Na'il Saleh Prof. Ali Trabolsi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4607-4613
Magnetic and fluorescent assemblies of iron‐oxide nanoparticles (NPs) were constructed by threading a viologen‐based ditopic ligand, DPV2+, into the cavity of cucurbituril (CB[7]) macrocycles adsorbed on the surface of the NPs. Evidence for the formation of 1:2 inclusion complexes that involve DPV2+ and two CB[7] macrocycles was first obtained in solution by 1H NMR and emission spectroscopy. DPV2+ was found to induce self‐assembly of nanoparticle arrays (DPV2+?CB[7]NPs) by bridging CB[7] molecules on different NPs. The resulting viologen‐crosslinked iron‐oxide nanoparticles exhibited increased saturation magnetization and emission properties. This facile supramolecular approach to NP self‐assembly provides a platform for the synthesis of smart and innovative materials that can achieve a high degree of functionality and complexity and that are needed for a wide range of applications. 相似文献
75.
Cover Picture: Viologen‐Templated Arrays of Cucurbit[7]uril‐Modified Iron‐Oxide Nanoparticles (Chem. Eur. J. 12/2015) 下载免费PDF全文
76.
Beatriz M. de Campos Paulo S. Calefi Katia J. Ciuffi Emerson H. de Faria Lucas A. Rocha Eduardo J. Nassar Jorge V. L. Silva Marcelo F. Oliveira Izaque A. Maia 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1029-1035
The combination of sol–gel methodology with rapid prototyping (RP) produces functionalized 3D structures with potential applications in various fields. However, this combination has been little explored. In this paper, we used the sol–gel method to deposit vanadium isopropoxide onto polyamide (PA12) constructed by RP and pretreated with acetic acid, to obtain a functionalized substrate with new thermal, physical, and chemical properties. Vanadium isopropoxide (one, five, or ten layers) was deposited onto the PA12 piece by dip-coating. We characterized the coated PA12 by thermal analyses, X-ray diffraction, and infrared spectroscopy, which revealed that V=O and Si–O–Si groups exist on the PA12 surface. PA12 coating with vanadium isopropoxide enhanced the decomposition temperature. Differential scanning calorimetry revealed increased fusion and decomposition enthalpy as a function of the PA12 coating. Therefore, deposition of vanadium isopropoxide onto PA12 pretreated with acetic acid improves the thermal stability of PA12 prepared by RP. 相似文献
77.
In this paper we study a nonlinear filtering problem for a general Markovian partially observed system (X,Y), whose dynamics is modeled by correlated jump-diffusions having common jump times. At any time t∈[0,T], the σ-algebra $\mathcal{F}^{Y}_{t}:= \sigma\{ Y_{s}: s\leq t\}$ provides all the available information about the signal X t . The central goal of stochastic filtering is to characterize the filter, π t , which is the conditional distribution of X t , given the observed data $\mathcal{F}^{Y}_{t}$ . In Ceci and Colaneri (Adv. Appl. Probab. 44(3):678–701, 2012) it is proved that π is the unique probability measure-valued process satisfying a nonlinear stochastic equation, the so-called Kushner-Stratonovich equation (in short KS equation). In this paper the aim is to improve the hypotheses to obtain the KS equation and describe the filter π in terms of the unnormalized filter ?, which is solution of a linear stochastic differential equation, the so-called Zakai equation. We prove the equivalence between strong uniqueness of the solution of the KS equation and strong uniqueness of the solution of the Zakai one and, as a consequence, we deduce pathwise uniqueness of the solution of the Zakai equation by applying the Filtered Martingale Problem approach (Kurtz and Ocone in Ann. Probab. 16:80–107, 1988; Ceci and Colaneri in Adv. Appl. Probab. 44(3):678–701, 2012). To conclude, we discuss some particular models. 相似文献
78.
Katia Barbera Leone Frusteri Giuseppe Italiano Lorenzo Spadaro Francesco Frusteri Siglinda Perathoner Gabriele Centi 《催化学报》2014,35(6):869-876
The investigation by SEM/TEM, porosity, and X-ray diffraction measurements of the graphitization process starting from amorphous carbon nanospheres, prepared by glucose carbonization, is reported. Aspects studied are the annealing temperature in the 750–1000 °C range, the type of inert carrier gas, and time of treatment in the 2–6 h range. It is investigated how these parameters influence the structural and morphological characteristics of the carbon materials obtained as well as their nanostructure. It is shown that it is possible to maintain after graphitization the round-shaped macro morphology, a high surface area and porosity, and especially a large structural disorder in the graphitic layers stacking, with the presence of rather small ordered domains. These are characteristics interesting for various catalytic applications. The key in obtaining these characteristics is the thermal treatment in a flow of N2. It was demonstrated that the use of He rather than N2 does not allow obtaining the same results. The effect is attributed to the presence of traces of oxygen, enough to create the presence of oxygen functional groups on the surface temperatures higher than 750 °C, when graphitization occurs. These oxygen functional groups favor the graphitization process. 相似文献
79.
Tavani M Marisaldi M Labanti C Fuschino F Argan A Trois A Giommi P Colafrancesco S Pittori C Palma F Trifoglio M Gianotti F Bulgarelli A Vittorini V Verrecchia F Salotti L Barbiellini G Caraveo P Cattaneo PW Chen A Contessi T Costa E D'Ammando F Del Monte E De Paris G Di Cocco G Di Persio G Donnarumma I Evangelista Y Feroci M Ferrari A Galli M Giuliani A Giusti M Lapshov I Lazzarotto F Lipari P Longo F Mereghetti S Morelli E Moretti E Morselli A Pacciani L Pellizzoni A Perotti F Piano G 《Physical review letters》2011,106(1):018501
Strong electric discharges associated with thunderstorms can produce terrestrial gamma-ray flashes (TGFs), i.e., intense bursts of x?rays and γ?rays lasting a few milliseconds or less. We present in this Letter new TGF timing and spectral data based on the observations of the Italian Space Agency AGILE satellite. We determine that the TGF emission above 10 MeV has a significant power-law spectral component reaching energies up to 100 MeV. These results challenge TGF theoretical models based on runaway electron acceleration. The TGF discharge electric field accelerates particles over the large distances for which maximal voltages of hundreds of megavolts can be established. The combination of huge potentials and large electric fields in TGFs can efficiently accelerate particles in large numbers, and we reconsider here the photon spectrum and the neutron production by photonuclear reactions in the atmosphere. 相似文献
80.
Yassine Oulad El Majdoub Filippo Alibrando Francesco Cacciola Katia Arena Eleonora Pagnotta Roberto Matteo Giuseppe Micalizzi Laura Dugo Paola Dugo Luigi Mondello 《Molecules (Basel, Switzerland)》2020,25(22)
Indian mustard or Brassica juncea (B. juncea) is an oilseed plant used in many types of food (as mustard or IV range salad). It also has non-food uses (e.g., as green manure), and is a good model for phytoremediation of metals and pesticides. In recent years, it gained special attention due to its biological compounds and potential beneficial effects on human health. In this study, different tissues, namely leaves, stems, roots, and flowers of three accessions of B. juncea: ISCI 99 (Sample A), ISCI Top (Sample B), and “Broad-leaf” (Sample C) were analyzed by HPLC-PDA/ESI-MS/MS. Most polyphenols identified were bound to sugars and phenolic acids. Among the three cultivars, Sample A flowers turned were the richest ones, and the most abundant bioactive identified was represented by Isorhamnetin 3,7-diglucoside (683.62 µg/100 mg dry weight (DW) in Sample A, 433.65 µg/100 mg DW in Sample B, and 644.43 µg/100 mg DW in Sample C). In addition, the most complex samples, viz. leaves were analyzed by GC-FID/MS. The major volatile constituents of B. juncea L. leaves extract in the three cultivars were benzenepropanenitrile (34.94% in Sample B, 8.16% in Sample A, 6.24% in Sample C), followed by benzofuranone (8.54% in Sample A, 6.32% in Sample C, 3.64% in Sample B), and phytone (3.77% in Sample B, 2.85% in Sample A, 1.01% in Sample C). The overall evaluation of different tissues from three B. juncea accessions, through chemical analysis of the volatile and non-volatile compounds, can be advantageously taken into consideration for future use as dietary supplements and nutraceuticals in food matrices. 相似文献