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761.
The maximum entropy approach used together with fractional moments has proven to be a flexible and powerful tool for density approximation of a positive random variable. In this paper we consider an optimality criterion based on the Kullback–Leibler distance in order to select appropriate fractional moments. We discuss the properties of the proposed procedure when all the available information comes from a sample of observations. The method is applied to the size distribution of the U.S. family income. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
762.
Luciano Callipo Patrizia Foglia Riccardo Gubbiotti Roberto Samperi Aldo Laganà 《Analytical and bioanalytical chemistry》2009,394(3):811-820
A method for carbonic anhydrase II (CA II) absolute quantification in human serum is presented. This method is based on high-performance
liquid chromatography (HPLC)-Chip microfluidic device incorporating a nanoelectrospray source interfaced to a triple quadrupole
mass spectrometer. The fraction containing CA II was isolated by preparative reversed-phase HPLC, and peptides obtained from
the tryptic digest of the protein mixture were separated by the HPLC-Chip system. The multiple-reaction monitoring acquisition
mode of a selected suitable CA II peptide and peptide internal standard allowed the selective and sensitive determination
of a CA II. Absolute recovery of the method was 52 ± 12%, while analytical recovery was 81 ± 10%. For the eight samples analyzed,
the matrix effect was found to be only −14 ± 6%. A comparison among three regression lines type which were obtained by external
calibration, matrix-matched calibration, and standard addition method, respectively, demonstrated that the first one is adequate
in obtaining good accuracy and precision. Method quantification limit for CA II in serum was estimated to be 2 fmol/mL. CA
II mean concentration in sera from eight healthy subjects was found to be 56 pmol/mL (relative standard deviation 24%). 相似文献
763.
Julia Böttcher Yoshiharu Kohayakawa Aldo Procacci 《Random Structures and Algorithms》2012,40(4):425-436
Let G be a graph on n vertices with maximum degree Δ. We use the Lovász local lemma to show the following two results about colourings χ of the edges of the complete graph Kn. If for each vertex v of Kn the colouring χ assigns each colour to at most (n ‐ 2)/(22.4Δ2) edges emanating from v, then there is a copy of G in Kn which is properly edge‐coloured by χ. This improves on a result of Alon, Jiang, Miller, and Pritikin [Random Struct. Algorithms 23(4), 409–433, 2003]. On the other hand, if χ assigns each colour to at most n/(51Δ2) edges of Kn, then there is a copy of G in Kn such that each edge of G receives a different colour from χ. This proves a conjecture of Frieze and Krivelevich [Electron. J. Comb. 15(1), R59, 2008]. Our proofs rely on a framework developed by Lu and Székely [Electron. J. Comb. 14(1), R63, 2007] for applying the local lemma to random injections. In order to improve the constants in our results we use a version of the local lemma due to Bissacot, Fernández, Procacci, and Scoppola [preprint, arXiv:0910.1824]. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 40, 425–436, 2012 相似文献
764.
Rodrigo V. Salvatierra Luciano G. Moura Marcela M. Oliveira Marcos A. Pimenta Aldo J. G. Zarbin 《Journal of Raman spectroscopy : JRS》2012,43(8):1094-1100
Thin, transparent, and self‐assembled films of neat polyaniline and polyaniline/carbon nanotube nanocomposites were deposited over glass substrates by interfacial polymerization. The effect of the carbon nanotubes on the structure and conformation of the polyaniline, and the type of interaction between the polymer and the nanotubes, have been studied by resonant Raman spectroscopy and UV–Vis and Raman spectroelectrochemistry. The results indicate clearly that the carbon nanotubes induce important changes in the electronic structure of the polymer, resulting in a more polaronic organization. Additionally, an effective interaction between the polymer and the nanotube, based on a polyaniline‐to‐nanotube charge transfer, is proposed in this work. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
765.
In this work we analyze the connection between information theory and thermodynamics. Three different potentials are presented, all related to the Kullback–Leibler divergence. These potentials represent three different conditions of energy and information exchange between a reservoir and a subsystem. The first potential describes a situation where the two systems are exchanging energy without any external control. The second potential considers the situation where the reservoir can get information through the state of another secondary system about the internal state of the subsystem. This information can then be used by a Maxwell demon to increase the free energy of the subsystem. In this second scenario it is assumed that the energy cost of the information probe and the Maxwell demon are at the expense of the reservoir. Finally, a third case is considered where the information obtained through the secondary system is used not only to manipulate an internal Maxwell demon, but to perform directly work over the subsystem. This last case involves a direct modification of the Hamiltonian of the subsystem. 相似文献
766.
C Scapolla G Cangemi S Barco L Barbagallo D Bugnone A Maffia G Melioli A Profumo U Benatti G Damonte 《Journal of mass spectrometry : JMS》2012,47(7):816-824
The levels of urinary catecholamine metabolites, such as homovanillic acid (HVA) and vanillylmandelic acid, are routinely used as a clinical tool in the diagnosis and follow-up of neuroblastoma (NB) patients. Recently, in the Clinical Pathology Laboratory Unit of G. Gaslini Children Hospital, a commercial method that employs liquid chromatography coupled to electrochemical detection (LC-EC) has been introduced for the measurement of these metabolites in the routine laboratory practice. Using this LC-EC method, an unknown peak could be observed only in samples derived from NB patients. To investigate the nature of this peak, we used a combination of liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) and liquid chromatography-ion trap tandem mass spectrometry (LC-IT-MS). The first approach was used to obtain the elemental composition of the ions present in this new signal. To get additional structural information useful for the elucidation of unknown compounds, the ion trap analyzer was exploited. We were able to identify not just one, but three unknown signals in urine samples from NB patients which corresponded to three conjugated products of HVA: HVA sulfate and two glucuronoconjugate isomers. The enzymatic hydrolysis with β-glucuronidase confirmed the proposed structures, while the selective alkaline hydrolysis allowed us to distinguish the difference between phenol- and acyl-glucuronide of HVA. The latter was the unknown peak observed in LC-EC separations of urine samples from NB patients. 相似文献
767.
Abraham Alberto Ramírez-Mendoza Mario Alberto Ramírez-Herrera Cesar Ricardo Cortez-lvarez Sendar Daniel Nery-Flores Aldo Rafael Tejeda-Martínez Marina María de Jesús Romero-Prado María Luisa Mendoza-Magaa 《Molecules (Basel, Switzerland)》2022,27(14)
Ozone (O3) is an oxidating tropospheric pollutant. When O3 interacts with biological substrates, reactive oxygen and nitrogen species (RONS) are formed. Severe oxidative damage exhausts the endogenous antioxidant system, which leads to the decreased activity of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). Curcumin (CUR) is a natural polyphenol with well-documented antioxidant and anti-inflammatory properties. The aim of this work is to evaluate the effects of curcumin on CAT, GPx, and SOD activity and the inhibition of oxidative damage after the acute and chronic exposure to O3. Fifty male Wistar rats were divided into five experimental groups: the intact control, CUR-fed control, exposed-to-O3 control, CUR-fed (preventive), and CUR-fed (therapeutic) groups. These two last groups received a CUR-supplemented diet while exposed to O3. These experiments were performed during acute- and chronic-exposure phases. In the preventive and therapeutic groups, the activity of plasma CAT, GPx, and SOD was increased during both exposure phases, with slight differences; concomitantly, lipid peroxidation and protein carbonylation were inhibited. For this reason, we propose that CUR could be used to enhance the activity of the antioxidant system and to diminish the oxidative damage caused by exposure to O3. 相似文献
768.
The computed tomography (CT) chest is a tool for diagnostic tests and the early evaluation of lung infections, pulmonary interstitial damage, and complications caused by common pneumonia and COVID-19. Additionally, computer-aided diagnostic systems and methods based on entropy, fractality, and deep learning have been implemented to analyse lung CT images. This article aims to introduce an Entropy-based Measure of Complexity (EMC). In addition, derived from EMC, a Lung Damage Measure (LDM) is introduced to show a medical application. CT scans of 486 healthy subjects, 263 diagnosed with COVID-19, and 329 with pneumonia were analysed using the LDM. The statistical analysis shows a significant difference in LDM between healthy subjects and those suffering from COVID-19 and common pneumonia. The LDM of common pneumonia was the highest, followed by COVID-19 and healthy subjects. Furthermore, LDM increased as much as clinical classification and CO-RADS scores. Thus, LDM is a measure that could be used to determine or confirm the scored severity. On the other hand, the d-summable information model best fits the information obtained by the covering of the CT; thus, it can be the cornerstone for formulating a fractional LDM. 相似文献
769.
Antonino Pollicino Valentina Siracusa Roberta Bongiovanni Aldo Priola 《Macromolecular rapid communications》1995,16(11):807-812
A preliminary X-ray photoelectron spectroscopic (XPS) investigation on poly[4,4′-isopropylidenebis(1,4-phenyleneoxyethylene) diacrylate] samples obtained by photocuring on several substrates in the presence of a fluorine containing acrylic monomer is reported. Quantitative calculations based on F1s/C1s area ratios and C1s peak fitting show a noticeable fluorine surface enrichment that ranges, depending on the substrate, from 17 wt.-% to 59 wt.-% of fluorine containing moiety. The calculations also reveal the presence of a concentration gradient at the surface. 相似文献
770.