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441.
B. V. Robouch I. V. Kutcherenko M. Cestelli Guidi A. Kisiel A. Marcelli P. Robouch M. Piccinini A. Nucara R. Triboulet E. Burattini J. Cebulski E. M. Sheregii J. Polit 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,84(2):183-195
Similar ternary semiconductors are sometimes associated with widely different structures characterized by different site occupation preferences. We have used far-infrared (FIR) spectra to determine the site occupation preference coefficients for three ternary semiconductor alloys: ZnCdTe, ZnHgTe and CdHgTe and, in the case of ZnHgTe, have validated it by X-ray absorption fine structure (EXAFS) analysis. While ZnCdTe spectra exhibit the canonical configuration with eight phonon lines free of vibrational defect lines and only a slight departure from a random ion distribution, CdHgTe spectra show the eight canonical phonon modes plus an additional vibrational defect line and constant preference coefficients. In contrast, two defect lines and only four modes characterize ZnHgTe spectra, as extreme preferences prevent the formation of two of the five expected tetrahedral configuration arrangements. Moreover, for this system, comparison with EXAFS data points out the vibrational nature of both the extra lines. The analysis clearly shows that assuming a Bernoulli distribution of the component configurations of semiconductors may lead to wrong assessments of the evolution of its properties with relative content. 相似文献
442.
Brunilde Castano Tommaso Pedrazzini Massimo Sisti Emma Gallo Fabio Ragaini Nicola Casati Alessandro Caselli 《应用有机金属化学》2011,25(11):824-829
The synthesis and characterization of copper(I) complexes of the novel pyridine‐containing macrocyclic ligand (PC‐L) and their use as catalysts in the Henry reaction are reported. The pyridine‐based 12‐membered tetraaza macrocyclic (PC‐L) ligand 1 can be obtained in good overall yield (85%) from commercially available starting materials. The Cu(I) complexes showed good catalytic activities in the Henry reaction of different aldehydes and nitroalkanes. Remarkable diastereoselectivity was observed when isatine was reacted with nitroethane under catalytic conditions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
443.
Tommaso Flaminio 《Archive for Mathematical Logic》2007,46(3-4):301-319
In this paper we investigate the problem of testing the coherence of an assessment of conditional probability following a
purely logical setting. In particular we will prove that the coherence of an assessment of conditional probability χ can be
characterized by means of the logical consistency of a suitable theory T
χ defined on the modal-fuzzy logic FP
k
(RŁΔ) built up over the many-valued logic RŁΔ. Such modal-fuzzy logic was previously introduced in Flaminio (Lecture Notes in Computer Science, vol. 3571, 2005) in order
to treat conditional probability by means of a list of simple probabilities following the well known (smart) ideas exposed
by Halpern (Proceedings of the eighth conference on theoretical aspects of rationality and knowledge, pp 17–30, 2001) and
by Coletti and Scozzafava (Trends Logic 15, 2002). Roughly speaking, such logic is obtained by adding to the language of RŁΔ a list of k modalities for “probably” and axioms reflecting the properties of simple probability measures. Moreover we prove that the satisfiability problem for
modal formulas of FP
k
(RŁΔ) is NP-complete. Finally, as main result of this paper, we prove FP
k
(RŁΔ) in order to prove that the problem of establishing the coherence of rational assessments of conditional probability is NP-complete.
相似文献
444.
N-acyl-homoserine-lactones (AHSLs) are widely conserved signal molecules present in quorum sensing systems of Gram-negative bacteria such as Pseudomonas aeruginosa. We present here the results obtained with a hybrid linear trap/Fourier transform ion cyclotron resonance (LTQ-FTICR) mass spectrometer used to investigate the occurrence of AHSLs and cognate N-acyl-homoserines (AHSs) in bacterial isolates of P. aeruginosa (strain PAO1). Two hydrolysed AHSs were found in significant amounts, most likely formed through the lactone opening of N-3-oxo-decanoyl-L-homoserine-lactone (3OC10-HSL) and N-3-oxo-dodecanoyl-L-homoserine-lactone (3OC12-HSL). Structure elucidation of these ring-opened molecules, i.e. N-3-oxo-decanoyl-L-homoserine (3OC10-HS), and N-3-oxo-dodecanoyl-L-homoserine (3OC12-HS), which are not detected by bacterial biosensors, was performed by high-resolution and accurate mass measurements upon liquid chromatography (LC) and confirmed by tandem MS in the LTQ analyser. Assignment of chemical formula, with mass spectra in the form of [M+H]+, was significantly expedited by extracted ion chromatograms (XICs) because the number of potentially plausible formulae for each protonated signalling molecule was considerably reduced a priori by the LC behaviour, the high mass measurement accuracy available in FTICR mass spectra and the isotopic patterns. At least two concentration levels were observed in spent culture supernatants of P. aeruginosa: compounds at a relatively high content (5-15 microM) that is C4-HSL, 3OC10-HS, and 3OC12-HS and those occurring at a lower content (<0.2 microM) that is C6-HSL and C8-HSL. The implications of this work extend to a great variety of Gram-negative bacteria. 相似文献
445.
446.
447.
448.
Tommaso Crisenza Hans‐Jürgen Butt Kaloian Koynov Roberto Simonutti 《Macromolecular rapid communications》2012,33(2):114-119
Blends of chlorinated polyethylene and nylon‐6/‐6,6/‐12 terpolyamide were prepared. The ratio of the two components was systematically varied within the blends. The mechanical behavior of the samples was analyzed with tensile tests and dynamical mechanical analysis showing that, for several ratios, materials with improved mechanical properties typical of thermoplastic elastomers were obtained. In such a mechanical regime, a co‐continuous phase‐separated morphology was clearly evidenced at the microscopic scale by 3D laser scanning confocal fluorescent microscopy (LSCFM). At blend compositions where plastic tensile behavior is observed, LSCFM reveals dispersed spheres of one component in the other. 相似文献
449.
Poli T Chiantore O Giovagnoli A Piccirillo A 《Analytical and bioanalytical chemistry》2012,402(9):2977-2984
The study of polished cross sections is a well-assessed and practical method to investigate the stratigraphy of paintings
and multilayer polychromies on works of art, in general. Analyses on cross sections allow us to characterize, at once, all
the layers in the stratigraphy, giving information about the artists technique, the number of layers and their composition
and sometimes about the conservation history of the artefact. In this paper, the application of an imaging detector focal
plane array (FPA) coupled to an infrared (IR) microscope has been studied, focusing on the characteristics and potential of
the different working methodologies (attenuated total reflectance (ATR) and total reflection). FPA detector coupled with ATR
crystal can “localize” IR information coming from a 30 × 30μm sample area, in a 64 × 64 dot matrix detector. In particular,
an innovative analysis methodology has been tested for the total reflectance measurements in order to obtain maximum information
with single measurements. Micro-infrared total reflection measurements have been carried out in an extended IR range (from
1,000 to 5,266 cm−1) exploiting the broad spectral response of mercury cadmium telluride detector in order to include overtones and combination
bands from near-infrared spectral range without any modification of the standard mid-infrared micro-FT instrumentation. The
potentialities of this new approach have been successfully transferred in the imaging/mapping investigations with a minimal
tuning of the apparatus. Results obtained on a polished cross section coming from a modern painting and on a micro-sample
of a wood polychromy from an undated historic polyptic are shown for demonstration. 相似文献
450.
This contribution reports the results obtained in the definition of a catalytic method for the nucleophilic ring opening of epoxides by activated methylenes promoted by a polymer-supported base. The attention has been focused on the use of polymer supported bases and the best results have been obtained by using 4-(dimethylamino)pyridine (PS-DMAP) and 2-tert-butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine both on polystyrene (PS-BEMP). Solvent-free conditions has been essential for reaching a sufficient reactivity to realize this process, in fact when a reaction medium is used, the processes are almost unfeasible. 相似文献