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991.
The chemistry of the HC(O)CO radical, produced in the oxidation of glyoxal, has been studied under conditions relevant to the lower atmosphere using an environmental chamber/Fourier Transform infrared spectrometric system. The chemistry of HC(O)CO was studied over the range 224–317 K at 700 Torr total pressure and was found to be governed by competition between unimolecular decomposition [to HCO and CO, reaction (5)] and reaction with O2 [to form HO2 and 2CO, reaction (6a), or HC(O)C(O)O2, reaction (6b)]. The rate coefficient for decomposition relative to that of reaction with O2 increases with increasing temperature. Assuming a value for k6 of 10−11 cm3 molecule−1 s−1, the following expression for the unimolecular decomposition is obtained at 700 Torr, k5 = 1.4+9/−1.1 × 1012 exp(−3160 ± 500/T). The rate coefficients for reactions (6a) and (6b) are about equal, with no strong dependence on temperature. The reaction of HC(O)C(O)O2 with NO2 was also studied. Final product analysis was consistent with the formation of HCO, CO2, and NO3 as the major products in this reaction; no evidence for the PAN‐type species, HC(O)C(O)O2NO2, was found even at the lowest temperature studied (224 K). The UV‐visible absorption spectrum of glyoxal is also reported; results are in substantive agreement with previous studies. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 149–156, 2001 相似文献
992.
993.
Within the Landau–de Gennes theory, the order parameter describing a biaxial nematic liquid crystal assigns a symmetric traceless 3 × 3 matrix Q with three distinct eigenvalues to every point of the region Ω occupied by the system. In the constrained case of matrices Q with constant eigenvalues, the order parameter space is diffeomorphic to the eightfold quotient ${\mathbb{S}^3/\mathcal{H}}$ of the 3-sphere ${\mathbb{S}^3}$ , where ${\mathcal{H}}$ is the quaternion group, and a configuration of a biaxial nematic liquid crystal is described by a map from Ω to ${\mathbb{S}^3/\mathcal{H}}$ . We express the (simplest form of the) Landau–de Gennes elastic free-energy density as a density defined on maps ${q: \Omega \to \mathbb{S}^3}$ , whose functional dependence is restricted by the requirements that (1) it is well defined on the class of configuration maps from Ω to ${\mathbb{S}^3/\mathcal{H}}$ (residual symmetry) and (2) it is independent of arbitrary superposed rigid rotations (frame indifference). As an application of this representation, we then discuss some properties of the corresponding energy functional, including coercivity, lower semicontinuity and strong density of smooth maps. Other invariance properties are also considered. In the discussion, we take advantage of the identification of ${\mathbb{S}^3}$ with the Lie group of unit quaternions ${Sp(1) \cong SU(2)}$ and of the relations between quaternions and rotations in ${\mathbb{R}^3}$ and ${\mathbb{R}^4}$ . 相似文献
994.
Cristina Danna Laura Cornara Antonella Smeriglio Domenico Trombetta Giuseppe Amato Pierluca Aicardi Laura De Martino Vincenzo De Feo Lucia Caputo 《Molecules (Basel, Switzerland)》2021,26(21)
The phytotoxicity and eco-compatibility of essential oils (EOs) from Eucalyptus gunnii (EG) and E. pulverulenta ‘Baby Blue’ (EP), cultivated in Italy for their cut foliage, were investigated. Leaf micromorphology, EOs phytochemical characterization, and phytotoxicity were analysed. EP revealed a significantly higher oil gland density and a higher EO yield with respect to EG. In both EOs, 1,8-cineole was the major compound (~75%), followed by α-pinene in EG (13.1%) and eugenol in EP (7.5%). EO phytotoxicity was tested on both weeds (Lolium multiflorum, Portulaca oleracea) and crops (Raphanus sativus, Lactuca sativa, Lepidium sativum, Solanum lycopersicum, Pisum sativum, Cucumis sativus). EG EO inhibited germination of P. oleracea, R. sativus, and S. lycopersicum seeds (ranging from 61.5 to 94.6% for the higher dose used), while affecting only radical elongation in S. lycopersicum (ranging from 66.7 to 82.6%). EP EO inhibited germination of P. oleracea and R. sativus (ranging from 41.3 to 74.7%) and affected radical elongation of L. sativum and L. multiflorum (ranging from 57.4 to 76.0%). None of the EOs affected the germination and radical growing of L. sativa, P. sativum, and C. sativus. Moreover, EP EO was more active than EG EO in inhibiting α-amylase, a key enzyme for seed growth regulation. Brine shrimp lethality assay showed that both EOs are safe for aquatic organisms, suggesting their high eco-compatibility. The data collected provide useful information for future applications of these EOs in agriculture as safe and selective bioherbicides. 相似文献
995.
Alessia Catalano Domenico Iacopetta Jessica Ceramella Domenica Scumaci Federica Giuzio Carmela Saturnino Stefano Aquaro Camillo Rosano Maria Stefania Sinicropi 《Molecules (Basel, Switzerland)》2022,27(3)
Multidrug resistance is a leading concern in public health. It describes a complex phenotype whose predominant feature is resistance to a wide range of structurally unrelated cytotoxic compounds, many of which are anticancer agents. Multidrug resistance may be also related to antimicrobial drugs, and is known to be one of the most serious global public health threats of this century. Indeed, this phenomenon has increased both mortality and morbidity as a consequence of treatment failures and its incidence in healthcare costs. The large amounts of antibiotics used in human therapies, as well as for farm animals and even for fishes in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. It is not negligible that the ongoing COVID-19 pandemic may further contribute to antimicrobial resistance. In this paper, multidrug resistance and antimicrobial resistance are underlined, focusing on the therapeutic options to overcome these obstacles in drug treatments. Lastly, some recent studies on nanodrug delivery systems have been reviewed since they may represent a significant approach for overcoming resistance. 相似文献
996.
Salvatore Capozziello Rocco D’Agostino Orlando Luongo 《General Relativity and Gravitation》2017,49(11):141
We propose a model-independent formalism to numerically solve the modified Friedmann equations in the framework of f(T) teleparallel cosmology. Our strategy is to expand the Hubble parameter around the redshift \(z=0\) up to a given order and to adopt cosmographic bounds as initial settings to determine the corresponding \(f(z)\equiv f(T(H(z)))\) function. In this perspective, we distinguish two cases: the first expansion is up to the jerk parameter, the second expansion is up to the snap parameter. We show that inside the observed redshift domain \(z\le 1\), only the net strength of f(z) is modified passing from jerk to snap, whereas its functional behavior and shape turn out to be identical. As first step, we set the cosmographic parameters by means of the most recent observations. Afterwards, we calibrate our numerical solutions with the concordance \(\Lambda \)CDM model. In both cases, there is a good agreement with the cosmological standard model around \(z\le 1\), with severe discrepancies outer of this limit. We demonstrate that the effective dark energy term evolves following the test-function: \(f(z)={\mathcal {A}}+{\mathcal {B}}{z}^2e^{{\mathcal {C}}{z}}\). Bounds over the set \(\left\{ {\mathcal {A}}, {\mathcal {B}}, {\mathcal {C}}\right\} \) are also fixed by statistical considerations, comparing discrepancies between f(z) with data. The approach opens the possibility to get a wide class of test-functions able to frame the dynamics of f(T) without postulating any model a priori. We thus re-obtain the f(T) function through a back-scattering procedure once f(z) is known. We figure out the properties of our f(T) function at the level of background cosmology, to check the goodness of our numerical results. Finally, a comparison with previous cosmographic approaches is carried out giving results compatible with theoretical expectations. 相似文献
997.
The KLOE- collaboration A. Anastasi D. Babusci G. Bencivenni M. Berlowski C. Bloise F. Bossi P. Branchini A. Budano L. Caldeira Balkest?hl B. Cao F. Ceradini P. Ciambrone F. Curciarello E. Czerwinski G. D’Agostini E. Danè V. De Leo E. De Lucia A. De Santis P. De Simone A. Di Cicco A. Di Domenico R. Di Salvo D. Domenici A. D’Uffizi A. Fantini G. Felici S. Fiore A. Gajos P. Gauzzi G. Giardina S. Giovannella E. Graziani F. Happacher L. Heijkenskj?ld W. Ikegami Andersson T. Johansson D. Kaminska W. Krzemien A. Kupsc S. Loffredo G. Mandaglio M. Martini M. Mascolo R. Messi S. Miscetti G. Morello D. Moricciani P. Moskal M. Papenbrock A. Passeri V. Patera E. Perez del Rio A. Ranieri P. Santangelo I. Sarra M. Schioppa M. Silarski F. Sirghi L. Tortora G. Venanzoni W. Wislicki M. Wolke 《Journal of High Energy Physics》2016,2016(5):19
998.
Cristina Occhiuto Gianluigi Aliberto Mariarosaria Ingegneri Domenico Trombetta Clara Circosta Antonella Smeriglio 《Molecules (Basel, Switzerland)》2022,27(11)
Recently, there has been a growing interest in the recovery of agri-food waste within the circular economy perspective. In this study, the nutritional, phytochemical, and biological features of the cold-pressed hempseed oil (HSO) and hempseed meal (HSM) of two industrial hemp varieties (USO 31 and Futura 75, THC ≤ 0.2%) were evaluated. The HSOs showed a high total phenols and flavonoid content, which were confirmed by LC-DAD-ESI-MS analysis, with rutin as the most abundant compound (56.93–77.89 µg/100 FW). They also proved to be a rich source of tocopherols (81.69–101.45 mg/100 g FW) and of a well-balanced ω-6 to ω-3 fatty acid ratio (3:1) with USO 31, which showed the best phytochemical profile and consequently the best antioxidant activity (about two times higher than Futura 75). The HSMs still retained part of the phytochemicals identified in the HSOs (polyphenols, tocopherols, and the preserved ω-6/ω-3 fatty acids ratio) and a modest antioxidant activity. Furthermore, they showed a very interesting nutritional profile, which was very rich in proteins (29.88–31.44 g/100 g FW), crude fibers (18.39–19.67 g/100 g), and essential and non-essential amino acids. Finally, only a restrained amount of anti-nutritional factors (trypsin inhibitors, phytic acid, and condensed tannins) was found, suggesting a promising re-use of these byproducts in the nutraceutical field. 相似文献
999.
1000.
Francesco Mallamace Carmelo Corsaro Domenico Mallamace Cirino Vasi Nicola Cicero H. Eugene Stanley 《Frontiers of Physics》2015,10(5):106105
The dynamic or glass transition in biomolecules is important to their functioning. Also essential is the transition between the protein native state and the unfolding process. To better understand these transitions, we use Fourier transform infrared spectroscopy to study the vibrational bending and stretching modes of hydrated lysozymes across a wide temperature range. We find that these transitions are triggered by the strong hydrogen bond coupling between the protein and hydration water. More precisely, we demonstrate that in both cases the water properties dominate the evolution of the system. We find that two characteristic temperatures are relevant: in the supercooled regime of confined water, the fragile-to-strong dynamic transition occurs at TL, and in the stable liquid phase, T * ≃ 315 ± 5 K characterizes the behavior of both isothermal compressibility KT (T,P) and the coefficient of thermal expansion aP (T,P). 相似文献