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91.
Tobat P.I. Saragi Christoph Schmidt Tanja Weis Arno Ehresmann 《Journal of magnetism and magnetic materials》2009,321(14):2204-2209
The surface and interface morphology and magnetization characteristics of Co70Fe30 thin films deposited on bare glass and p-Si/SiO2 substrates and on conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) thin films on such substrates have been studied by atomic force microscopy and magneto-optic Kerr effect. It was found that the average absolute magnitude of the coercive field of Co70Fe30 correlates with the roughness of the underlayer prior to Co70Fe30 deposition. P3HT deposited on p-Si/SiO2 substrates possesses an increased surface roughness as compared to the p-Si/SiO2 surface, but displays a decreased surface roughness as compared to the one of a bare glass substrate. 相似文献
92.
Vuyisa Sigwela Maryna De Wit Alba du Toit Gernot Osthoff Arno Hugo 《Molecules (Basel, Switzerland)》2021,26(16)
Natural food items and the additional benefits they provide have received considerable attention in recent years. Betalains are nutritious pigments which have valuable biological properties, e.g., antioxidant and free radical scavenging activity. In this study, aqueous betalain extracts were obtained from different coloured cactus pears (purple, red/pink, and orange), amaranth, and beetroot, with and without the addition of ascorbic acid, microwave-heated, and freeze-dried and subsequently analysed by thin layer chromatography (TLC). Beetroot samples without the addition of ascorbic acid (AA) had lower phenols, flavonoids, and ascorbic acid content than beetroot samples extracted with the addition of AA. Amaranth had significantly higher contents of antioxidants than all the other plants. Results for phenolic compounds showed that there were no significant differences between cactus pear cultivars, however, significant differences were seen between the two beetroot samples (microwave-heated with and without AA) as well as amaranth. For flavonoid compounds, amaranth had significantly higher values than all other samples. The lowest flavonoid content was found in beetroot without AA (0.49 mgCE/g). For ascorbic acid, significant differences were noticed between amaranth (71.71 mg/100 g) and samples from cactus pear and beetroot. TLC results showed that purple and red cactus pear samples had the most vivid colours, a reflection of the high betacyanin and betaxanthin contents in the cultivars. Moreover, extracts from cactus pear, beetroot, and amaranth were classified according to a decision tree which was designed by the Code of Federal Regulations/Food Additives Regulation of the EU. The classification of betalain pigment extracts as colouring foods was achieved through enrichment factor calculations and the colourant decision tree. The results showed that the betalain pigment extraction method used is inexpensive, time-saving, energy-saving, non-toxic, and chemical solvent free and yields high concentrations of betalains. 相似文献
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Adsorption isotherms of carbon dioxide were measured on cation-exchanged (Li+, Na+, K+, Cs+) MCM-22 zeolite with the molar ratio of Si/Al=15 and series of Na-MCM-22 of Si/Al molar ratios varying in the range from
15 to 40 at 273, 293, 313 and 333 K. Based on the known temperature dependence of CO2 adsorption, isosteric heats of adsorption were calculated. The obtained dependences of isosteric heats related to the amount
of CO2 adsorbed have provided detailed insight into the interaction of carbon dioxide molecule with alkali metal cations. 相似文献
95.
Arno Behr Prof. Dr. Marc Becker Dipl.‐Ing. Thomas Beckmann Dipl.‐Ing. Leif Johnen Dipl.‐Chem. Julia Leschinski Dipl.‐Ing. Sebastian Reyer Dipl.‐Chem. 《Angewandte Chemie (International ed. in English)》2009,48(20):3598-3614
A chameleonic reaction : The transition‐metal‐catalyzed telomerization of 1,3‐dienes with different nucleophiles leads to the synthesis of numerous products which can be applied in the cosmetic and pharmaceutical industry as well as in polymers and flavors. This Review shows the versatility of the telomerization based on recent research and industrial applications.
96.
Steinbrink J Villringer A Kempf F Haux D Boden S Obrig H 《Magnetic resonance imaging》2006,24(4):495-505
Functional magnetic resonance imaging (fMRI) is currently combined with electrophysiological methods to identify the relationship between neuronal activity and the blood oxygenation level-dependent (BOLD) signal. Several processes like neuronal activity, synaptic activity, vascular dilation, blood volume and oxygenation changes underlie both response modalities, that is, the electrophysiological signal and the vascular response. However, accessing single process relationships is absolutely mandatory when aiming at a deeper understanding of neurovascular coupling and necessitates studies on the individual building blocks of the vascular response. Combined fMRI and functional near-infrared spectroscopy studies have been performed to validate the correlation of the BOLD signal to the hemodynamic changes in the brain. Here we review the current status of the integration of both technologies and judge these studies in the light of recent findings on neurovascular coupling. 相似文献
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Depending on the application of nanoparticles, certain characteristics of the product quality such as size, morphology, abrasion
resistance, specific surface, dispersibility and tendency to agglomeration are important. These characteristics are a function
of the physicochemical properties, i.e. the micromechanical properties of the nanostructured material. The micromechanical
properties of these nanostructured agglomerates such as the maximum indentation force, the plastic and elastic deformation
energy and the strength give information on the product properties, e.g. the efficiency of a dispersion process of the agglomerates,
and can be measured by nanoindentation. In this study a Berkovich indenter tip was used for the characterisation of model
aggregates out of sol–gel produced silica and precipitated alumina agglomerates with different primary particle morphologies
(dimension of 15–40 nm). In general, the effect of the primary particle morphology and the presence or absence of solid bonds
can be characterised by the measurement of the micromechanical properties via nanoindentation. The micromechanical behaviour
of aggregates containing solid bonds is strongly affected by the elastic–plastic deformation behaviour of the solid bonds
and the breakage of solid bonds. Moreover, varying the primary particle morphology for similar particle material and approximately
isotropic agglomerate behaviour the particle–particle interactions within the agglomerates can be described by the elementar
breaking stress according to the formula of Rumpf. 相似文献
100.
Daniel Reitz Arno Rauschenbeutel 《Optics Communications》2012,285(23):4705-4708
A double-helix optical trapping potential for cold atoms can be straightforwardly created inside the evanescent field of an optical nanofiber. It suffices to send three circularly polarized light fields through the nanofiber; two counterpropagating and far red-detuned with respect to the atomic transition and the third far blue-detuned. Assuming realistic experimental parameters, the transverse confinement of the resulting potential allows one to reach the one-dimensional regime with cesium atoms for temperatures of several μK. Moreover, by locally varying the nanofiber diameter, the radius and pitch of the double-helix can be modulated, thereby opening a realm of applications in cold-atom physics. 相似文献