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41.
Mario Giannella Fulvio Gualtieri Maria Luisa Stein 《Journal of heterocyclic chemistry》1971,8(3):397-403
The Posner reaction between coumarin and hydroxylamine was studied and extended to several substituted coumarins. Isolation of some significant reaction intermediates permitted rationalization of a possible reaction pathway. 相似文献
42.
Fulvio Ratto Paolo Matteini Francesca Rossi Roberto Pini 《Journal of nanoparticle research》2010,12(6):2029-2036
We report on a new sustainable approach to manipulate the optical behaviour and geometrical properties of gold nanorods in aqueous solutions by fine control of their overgrowth. In our approach, the overgrowth is realized by modulation of the reduction of the gold ions which are left as Au1+ after the primary step of the synthesis (typically as much as ~80% of the gold ions available in the growth solution). The progress of the reduction requires the gradual addition of ascorbic acid, which transforms the Au1+ into Au0 and may be performed in the original growth solution with no need for any further manipulation. By control of the total amount and rate of administration of the ascorbic acid, we prove the possibility to realize a systematic modulation of the average lengths, diameters, shapes (rod or dog-bone like), and light extinction of the nanoparticles. A slow overgrowth leads to a gradual enlargement of the lengths and diameters at almost constant shape. In contrast, a faster overgrowth results into a more complex modification of the overall shape of the gold nanorods. 相似文献
43.
Cioffi C Campidelli S Brunetti FG Meneghetti M Prato M 《Chemical communications (Cambridge, England)》2006,(20):2129-2131
The functionalisation of single wall carbon nanohorns via 1,3-dipolar cycloaddition has been achieved, and the products have been characterised by spectroscopy, microscopy and thermogravimetry. 相似文献
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Anna Szabó Rolando Pasquariello Pedro F. Costa Radmila Pavlovic Indi Geurs Koen Dewettinck Chris Vervaet Tiziana A. L. Brevini Fulvio Gandolfi Sandra Van Vlierberghe 《Macromolecular bioscience》2023,23(10):2300016
To provide prominent accessibility of fishmeal to the European population, the currently available, time- and cost-extensive feeding trials, which evaluate fish feed, should be replaced. The current paper reports on the development of a novel 3D culture platform, mimicking the microenvironment of the intestinal mucosa in vitro. The key requirements of the model include sufficient permeability for nutrients and medium-size marker molecules (equilibrium within 24 h), suitable mechanical properties (G' < 10 kPa), and close morphological similarity to the intestinal architecture. To enable processability with light-based 3D printing, a gelatin-methacryloyl-aminoethyl-methacrylate-based biomaterial ink is developed and combined with Tween 20 as porogen to ensure sufficient permeability. To assess the permeability properties of the hydrogels, a static diffusion setup is utilized, indicating that the hydrogel constructs are permeable for a medium size marker molecule (FITC-dextran 4 kg mol−1). Moreover, the mechanical evaluation through rheology evidence a physiologically relevant scaffold stiffness (G' = 4.83 ± 0.78 kPa). Digital light processing-based 3D printing of porogen-containing hydrogels results in the creation of constructs exhibiting a physiologically relevant microarchitecture as evidenced through cryo-scanning electron microscopy. Finally, the combination of the scaffolds with a novel rainbow trout (Oncorhynchus mykiss) intestinal epithelial cell line (RTdi-MI) evidence scaffold biocompatibility. 相似文献
47.
Fulvio Gesmundo Jonathan D. Hauenstein Christian Ikenmeyer J. M. Landsberg 《Foundations of Computational Mathematics》2016,16(3):599-635
We use algebraic geometry to study matrix rigidity and, more generally, the complexity of computing a matrix–vector product, continuing a study initiated in Kumar et al. (2009), Landsberg et al. (preprint). In particular, we (1) exhibit many non-obvious equations testing for (border) rigidity, (2) compute degrees of varieties associated with rigidity, (3) describe algebraic varieties associated with families of matrices that are expected to have super-linear rigidity, and (4) prove results about the ideals and degrees of cones that are of interest in their own right. 相似文献
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Fulvio Cacace Giulia de Petris Federico Pepi Marzio Rosi Antonio Sgamellotti 《Angewandte Chemie (International ed. in English)》1999,38(16):2408-2410
Complexes that undergo extensive molecular reorganization upon unimolecular metastable dissociation are obtained after ionization of atmospheric gases containing ozone and chlorofluorocarbons [Eq. (1)]. These unusual processes, which require fission of all bonds initially present in the CHX2 unit (X=Cl, F) and combination of C with one of the O atoms of ozone, were demonstrated and their mechanism rationalized by the joint application of mass spectrometric and theoretical methods. 相似文献
50.
The motion tracking enhancement technique (MTE) is a recently introduced method to improve the accuracy of tomographic PIV
measurements at seeding density higher than currently practiced. The working principle is based on the fact that the particle
field and its projections are correlated between the two exposures. Therefore, information from subsequent exposures can be
shared within the tomographic reconstruction process of a single object, which largely reduces the energy lost into ghost particles. The study follows a previous work based on synthetic particle images, showing that the MTE technique has an effect similar
to that of increasing the number of cameras. In the present analysis, MTE is applied to Tomographic PIV data from two time-resolved
experiments on turbulent shear flows: a round jet at Re = 5,000 (f
acq = 1,000 Hz) and a turbulent boundary layer at the trailing edge of an airfoil (Re
c = 370,000) measured at 12,000 Hz. The application of MTE is extended to the case of more than two recordings. The performance
is assessed comparing the results from a lowered number of cameras with respect to the full tomographic imaging system. The
analysis of the jet flow agrees with the findings of numerical simulations provided the results are scaled taking into account the concept of MTE efficiency based on the volume fraction where ghost-pairs (Elsinga et al. 2010a) are produced. When a large fraction of fluid has uniform motion (stagnant fluid surrounding the jet), only a moderate reduction
in ghost intensity is expected by MTE. Nevertheless, a visible recovery of reconstruction quality is observed for the 3-cameras system when
MTE is applied making use of 3 recordings. In the turbulent boundary layer, the objective is set to increase the seeding density
beyond current practice, and the experiments are performed at approximately 200,000 particles/megapixel. The measurement robustness
is monitored with the signal-to-noise ratio S/N for the cross-correlation analysis. An estimate of the precision error is
obtained for the turbulent boundary layer case following the peak height of the spatio-temporal cross-correlation function
(frozen-turbulence). The MTE approach appears to be essential for the increase in robustness and measurement precision at such seeding density. 相似文献