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81.
Martin?BauerEmail author Sarang?Joshi Klas?Modin 《Calculus of Variations and Partial Differential Equations》2017,56(4):113
The geometric approach to optimal transport and information theory has triggered the interpretation of probability densities as an infinite-dimensional Riemannian manifold. The most studied Riemannian structures are the Otto metric, yielding the \(L^2\)-Wasserstein distance of optimal mass transport, and the Fisher–Rao metric, predominant in the theory of information geometry. On the space of smooth probability densities, none of these Riemannian metrics are geodesically complete—a property desirable for example in imaging applications. That is, the existence interval for solutions to the geodesic flow equations cannot be extended to the whole real line. Here we study a class of Hamilton–Jacobi-like partial differential equations arising as geodesic flow equations for higher-order Sobolev type metrics on the space of smooth probability densities. We give order conditions for global existence and uniqueness, thereby providing geodesic completeness. The system we study is an interesting example of a flow equation with loss of derivatives, which is well-posed in the smooth category, yet non-parabolic and fully non-linear. On a more general note, the paper establishes a link between geometric analysis on the space of probability densities and analysis of Euler–Arnold equations in topological hydrodynamics. 相似文献
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Models developed previously by the authors that describe nonlinear adsorption, and simultaneous pore and surface diffusion
in a single particle, that are based on intraparticle quartic and parabolic concentration profile approximations, and that
utilize the summation of the gas and adsorbed phases approach in the material balance formulations, were further validated
under more diverse, yet more realistic, cycling conditions. Periodic square, sinusoidal and triangular wave functions were
used to more accurately represent the periodic boundary conditions that the external surface of an adsorbent particle may
be exposed to during repeated adsorption and desorption cycles in a fixed bed adsorber. Analytical solutions that describe
the periodic uptake and release of the adsorbate by the adsorbent were obtained for all three periodic wave functions, and
for both the quartic and parabolic profile approximations. By comparing the predictions obtained from both models with the
exact numerical solution, the superiority of the quartic model over the parabolic model was clearly demonstrated for all wave
functions, and for a wide range of adsorbate-adsorbent systems and bulk concentrations. Excellent agreement between the quartic
and exact models was obtained in most cases. In general, the predictions improved as the wave function changed more gradually
with time (triangular more gradual than sinusoidal and sinusoidal more gradual than square), as the degree of mathematical
linearity of the adsorbate-adsorbent system increased, and as the maximum external surface concentration decreased (an isotherm
nonlinearity effect). Subtle differences in the predictive ability of the new approximate models, stemming from the use of
the different wave functions, were exposed. Overall, these results exemplify the importance of comparing the predictive ability
of new approximate models that describe intraparticle transport under more diverse cycling conditions than are typically utilized
in the literature, which has been dominated by the square wave function. 相似文献
85.
Dighe Vidya V. Gursale Atish A. Sane Ramesh T. Menon Sasikumar Raje Shvetali C. 《平面色谱法杂志一现代薄层色谱法》2005,18(4):305-307
JPC – Journal of Planar Chromatography – Modern TLC - Eugenol is used as a flavor in the food industry, has a variety of biological activity, and can serve as a biomarker. Because... 相似文献
86.
Abstract— The origin of glow peaks (thermoluminescence) was investigated in isolated spinach chloroplasts and Euglena cells by pretreatment with various concentrations of 3-(3,4 dichlorophenyl)-1,1-dimethylurea (DCMU)?, different light intensities, and after mild heating at various temperatures. Experiments are also reported on subchloroplast fractions enriched in pigment systems I (PSI) or II (PSII) (prepared under conditions to reduce destruction of membranes by excessive detergent contact). These results provide the following, most likely, suggestion for the origin of glow peaks: (1) Z peak originates in metastable states; it is insensitive to DCMU, temperature (320–328 K), and appears only when other peaks are saturated (10 Wm-2). (2) Peak I involves the use of a reducing entity A (plastoquinone) beyond Q (the primary electron acceptor of pigment system II, PSII), or, of a high “S” state (charge accumulator) of oxygen evolving system; its intensity is dramatically reduced by low concentrations (1 μM) of DCMU, and, there is more of it in PSII than in PSI particles. (3) Peak II is due to reaction of Q- with the “S” states of the oxygen evolving system; its intensity increases upon the addition of low concentrations of DCMU, at the expense of peak I; it is most sensitive to mild heating, and there is more of it in PSII than in PSI particles. (4) Peak III was not studied here as it was not resolved in most of our preparations. (5) Peak IV is from both pigment system I and II; it is sensitive to heating (>50°C), is somewhat sensitive to DCMU, and is present in both PSI and PSII particles. (6) Peak V is from PSI; it is least sensitive to mild heating, and it is enriched in PSI particles. The present studies have extended our knowledge regarding the origin of glow peaks in spinach chloroplasts and Euglena cells; in particular, the involvement of the charge accumulating “S” states of oxygen evolution (for peaks I and II) and of system I (for peak V) are emphasized in this paper. 相似文献
87.
Capillary zone electrophoresis has been used for the determination of gatifloxacin from its pharmaceutical preparation (tablets), using fused silica capillary. Separation was performed after hydrodynamic injection; the separation was achieved by applying 21 Kv voltage. Phosphate buffer solution (pH 9.5) was used as separation electrolyte. Detection was at 280 nm using a UV- detector. Under these experimental conditions the analysis takes 8 min. A linearity range for gatifloxacin was between 20.0 g mL–1 to 60.0 g mL–1. The method was validated and was found to be specific, precise, accurate, reproducible and robust and can be applied for the routine analysis of gatifloxacin from formulation and bulk drug. 相似文献
88.
A simple, rapid, and precise reversed-phase high-performance liquid chromatographic method has been developed for simultaneous determination of losartan potassium, ramipril, and hydrochlorothiazide. The three drugs were separated on a 150 mm × 4.6 mm i.d., 5 μm particle, Cosmosil C18 column. The mobile phase was 0.025 m sodium perchlorate–acetonitrile, 62:38 (v/v), containing 0.1% heptanesulphonic acid, pH adjusted to 2.85 with orthophosphoric acid, at a flow rate of 1.0 mL min−1. UV detection was performed at 215 nm. The method was validated for linearity, accuracy, precision, and limit of quantitation. Linearity, accuracy, and precision were acceptable in the ranges 35–65 μg mL−1 for losartan, 1.75–3.25 μg mL−1 for ramipril, and 8.75–16.25 μg mL−1 for hydrochlorothiazide. 相似文献
89.
Morteza Maghrebi Abbas Ali Khodadadi Yadollah Mortazavi Ali Sane Mohsen Rahimi Yaser Shirazi Zviad Tsakadze Subodh Mhaisalkar 《Applied Physics A: Materials Science & Processing》2009,97(2):417-424
The mm-long carbon nanotube (CNT) arrays were grown in a floating catalyst reactor, using xylene-ferrocene and a small amount
of acetic acid as the feed. The CNT arrays deposited on a quartz substrate at several positions along the reactor were extensively
characterized using Raman spectroscopy, scanning electron microscopy, X-ray diffraction, high-resolution transmission electron
microscopy, and optical microscopy. Various characterization methods consistently reveal that the acetic acid additive to
the feed alleviates deposition of amorphous carbon layer, which gradually thickens CNTs along the reactor. The acetic acid
also resulted in a higher growth rate along the so-called growth window, where CNT arrays are deposited on the quartz substrate.
High-performance liquid chromatography of extracted byproducts (PAHs) confirmed the presence of some polycyclic aromatic hydrocarbons.
The solid weight of PAHs decreased upon addition of ferrocene as the catalyst precursor, as well as of acetic acid to xylene
feed. The results suggest that primary light products of xylene pyrolysis can be competitive reactants for both catalytic
and subsequent pyrolytic reactions. They may also be more efficient feeds for CNT growth than xylene itself. 相似文献
90.
JPC – Journal of Planar Chromatography – Modern TLC - A high performance thin layer chromatographic method has been developed for the determination of idebenone in pharmaceutical... 相似文献