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101.
102.
This paper has demonstrated the study on the adsorption kinetics of orthoxylene on silica gel with a novel experimental methodology. In the method, there was a differential adsorption bed (DAB) where the solid adsorbent always contacted with the same bulk concentration of the adsorbate vapor, and the DAB was monitored with near-infrared diffuse reflectance spectroscopy (NIRDRS) continuously as well as non-invasively. Local partial least squares (PLS) algorithm was suggested to replace normal global PLS method in multivariate calibration models for processing NIRDRS data, because the concentration of the adsorbate on the adsorbent varied greatly as the adsorption process was going on. In this way, we, conveniently as well as promptly, obtained instantaneous adsorption rates of several orthoxylene/silica gel adsorption processes under different conditions like partial pressure of orthoxylene vapor and velocity of gas, and discovered that the adsorption process was physical adsorption, and mainly controlled by external diffusion. 相似文献
103.
The convergences of three L1 spline methods for scattered data interpolation and fitting using bivariate spline spaces are studied in this paper. That is, L1 interpolatory splines, splines of least absolute deviation, and L1 smoothing splines are shown to converge to the given data function under some conditions and hence, the surfaces from these three methods will resemble the given data values. 相似文献
104.
105.
The influence of starvation (defined as the period without substrate) and shock loads on the performance of a moving bed sequencing
batch reactor degrading 4-chlorophenol (4CP) were investigated. The biomass was acclimated to biodegrade 100 mg/L of 4CP,
and the colonization of the packing material was followed. Two starvation periods and two shock loads were studied. The degradation
capacity of the suspended and the attached biomass present on the moving bed was also evaluated. The experiments showed that,
after the starvation period, the specific degradation rate decreased from 30.5 to 28.5 and 20 mg 4CP/gVSS/h, when starvation
periods of 24 and 48 h were applied, respectively. When two concentration peaks of 500 and 1,050 mg/L were applied, a loss
of 6% and 8% on the specific degradation rate, respectively, was also observed. The moving bed thus showed great robustness
against starvation periods and shock loads. Suspended biomass presented higher specific degradation rates, but attached biomass
did not generate a metabolite that is inhibitory when it accumulates. 相似文献
106.
Simulated moving bed (SMB) chromatography is often perceived in the pharmaceutical industry as chromatographic method for separating binary mixtures, like racemates. However, SMB can also be used for unbalanced separations, i.e. binary mixtures of varying compositions and multi-component mixtures. These less common application modes of isocratic SMB chromatography are exemplified for four different compounds (racemates and diastereomers) and discussed in view of the so-called 'triangle theory' from an industrial perspective. 相似文献
107.
Fluidization of Nano-size Particles 总被引:2,自引:0,他引:2
Fluidization and collapsing bed experiments were performed with 'Tullanox', 10nm diameter fumed silica. The minimum fluidization velocity was determined to be 0.0115m/s at the unusually low volume fraction of solids of 0.0077. The solids volume fraction was measured using a -ray densitometer. Fluidization was without large bubbles, with a high bed expansion ratio. The highest granular temperature was of the order of that of Geldart B particles, as measured by Cody et al. (1996). The sedimentation process was simulated using a two-fluid hydrodynamic model. The input into the model was a measured solids stress modulus and an agglomerate size determined from the settling curves. With these two rheological parameters, there was good agreement between the sedimentation theory and the experiment. This study shows that the standard collapse bed experiment used in industry is a good test of rheological properties of particles. 相似文献
108.
A novel pseudo simulated moving bed was suggested to separate a ternary mixture. A solvent gradient was created to make the solvent strength decreasing from zone II to zone III. Under suitable conditions, the least retained solute A moved forward and the most retained solute C moved backward in zones II and III whereas the medium retained solute B moved forward in zone II but backward in zone III to be trapped in the two zones consequently. Once the columns in zones II and III were saturated with solute B, the solvent dissolving the feed was introduced at the feed port to remove solute A from the raffinate-port and solute C from the extract-port. Finally, solute B was recovered from the extract port by stopping the liquid flow in zone II. This scheme was validated by the successful separation of dihydrocapsaicin from capsaicinoids. 相似文献
109.
Ribeiro MF Dias AC Santos JL Lima JL Zagatto EA 《Analytical and bioanalytical chemistry》2006,384(4):1019-1024
A novel strategy for utilization of solid reagents in flow analysis is proposed. Establishment of diffuse and reproducible
geometry enables the solid particles to be maintained in constant floating, reflux, and circulating motion inside a mini-chamber.
This is efficiently accomplished with pulsed flows, a characteristic of multi-pumping flow systems. Drawbacks inherent in
solid-phase packed columns, for example backpressure, preferential pathways, swelling, etc., and some limitations inherent
in immobilized reagents are minimised. Spectrophotometric determination of zinc in plants was selected as an application of
the technique. Dowex 1-X8 anionic resin was kept freely inside a mini-chamber. Zinc chloro-complexes were adsorbed on the
moving particles and derivatization with zincon was performed after elution. Analytical figures of merit and the potential
and limitations of the approach are discussed. 相似文献
110.