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81.
V. Henriques U. Klausen J. Race K. L. Zirm J. Benedict W. Zimmermann J. Robert S. W. Cole S. L. Leiboff B. S. Kahn B. Matsumoto L. Ambard F. Schmid T. Teorell S. Balachowski B. Bruns A. Fujita S. Kasahara F. Serio S. Fiandaca K. Lang O. Manasse H. Müller H. v. Pechmann G. Schmidt R. Willstätter H. Kraut O. Erbacher J. Sacks A. C. Jvy J. P. Burgess und J. E. Vandolah 《Fresenius' Journal of Analytical Chemistry》1933,93(1-2):64-80
Ohne Zusammenfassung 相似文献
82.
Carla Henriques Paulo Eduardo Oliveira 《Statistical Inference for Stochastic Processes》2008,11(1):77-91
Let X
n
, n ≥ 1, be a strictly stationary associated sequence of random variables, with common continuous distribution function F. Using histogram type estimators we consider the estimation of the two-dimensional distribution function of (X
1,X
k+1) as well as the estimation of the covariance function of the limit empirical process induced by the sequence X
n
, n ≥ 1. Assuming a convenient decrease rate of the covariances Cov(X
1,X
n+1), n ≥ 1, we derive uniform strong convergence rates for these estimators. The condition on the covariance structure of the variables
is satisfied either if Cov(X
1,X
n+1) decreases polynomially or if it decreases geometrically, but as we could expect, under the latter condition we are able
to establish faster convergence rates. For the two-dimensional distribution function the rate of convergence derived under
a geometrical decrease of the covariances is close to the optimal rate for independent samples.
相似文献
83.
Rob. Henriques 《欧洲无机化学杂志》1884,17(2):2668-2673
84.
Mariana Cristea Daniela Gheorghiu Ionita Maria Bruma B. C. Simionescu 《Journal of Thermal Analysis and Calorimetry》2008,93(1):63-68
Two aromatic polyimides and the corresponding poly(amic acid)s, with oxadiazole and para/meta phenoxyphenylene rings in the backbone, were synthesized and the structure — thermal properties correlation was followed
by dynamic mechanical analysis. Concerning the poly(amic acid)s, the glass transition domain was emphasized only for the compound
with meta-oriented rings because the process of imidization takes place with increasing temperature. A multiplex experiment was performed
to calculate the activation energy of the transition localized under 200°C. Consecutive heating-cooling-heating cycles were
accomplished. All phenomena are discussed by cross-examination of the storage modulus (E′), loss modulus (E″) and loss factor tanδ variation with temperature. 相似文献
85.
Magda Carvalho Henriques Maria Amparo F. Faustino Artur M. S. Silva Juliana Felgueiras Margarida Fardilha 《Journal of Coordination Chemistry》2017,70(14):2393-2408
The coordination of ruthenium(II) complexes to anionic oxygen-based donors are very rare. This study describes a simple, one-pot method for obtaining [ruthenium(II)(trithiacyclononane)(curcumin)(S-DMSO)]Cl (1) in 37% yield. The structural characterization of complex 1 by elemental analysis, FT-IR, 1-D and 2-D NMR, ESI+-MS as well as UV–vis and fluorescence spectroscopies are presented. The DNA-melting temperature (Tm) assay shows that salmon sperm DNA (smDNA) in the presence of complex 1 has a higher melting temperature, with ΔTm = 7.4 °C, while in the presence of curcumin the melting temperature remains unaltered. The in vitro cytotoxic activities of curcumin and complex 1 were investigated using the tumor human prostate cell line, PC-3, and the healthy cell line, PNT-2. Complex 1 is innocuous toward normal prostate epithelial cells and, whereas curcumin is toxic, with inhibition rates of ca. 35 and 65% at 50 and 80 μM, respectively. On the tumor cell line PC-3, complex 1 did not cause viability changes, whereas curcumin exhibited dose-dependent inhibition, with ca. 73% inhibition at the highest concentration tested, i.e. 80 μM. This study suggests that coordination with the trithiacyclononane ruthenium(II) scaffold stabilizes the photochemical properties of curcumin and strongly changes its biologic activity. 相似文献
86.
Torres MF Sales PS de Rossi RH Fernández MA 《Langmuir : the ACS journal of surfaces and colloids》2010,26(23):17858-17866
The mixed system of a nonionic hydrocarbon surfactant, polyoxyethylene (23) lauryl ether (Brij-35), and a perfluorinated surfactant, perfluorononanoic acid, was investigated by a combination of methods. The critical micelle concentrations (cmc's) have been determined over a wide range of sample compositions by fluorescence and UV-visible spectrophotometry using pyrene and N-(4-nitrophenyl) perfluorononanamide, respectively, as molecular probes. The values of the cmc's obtained were considerably different with the two techniques employed. Measurements of the (19)F nuclear magnetic resonance chemical shift of the same mixtures showed two breaks in the plots of Δδ(f) versus molar fraction of the perfluorinated surfactant. Conductivity and surface tension measurements also showed two breaks. The behavior is attributed to the formation of mixed micelles that change their composition when the fraction of the fluorinated compound increases and some segregation of the fluorinated compound takes place at a high total surfactant concentration. 相似文献
87.
This study investigated the organic and inorganic constituents of healthy leaves and Candidatus Liberibacter asiaticus (CLas)-inoculated leaves of citrus plants. The bacteria CLas are one of the causal agents of citrus greening (or Huanglongbing) and its effect on citrus leaves was investigated using laser-induced breakdown spectroscopy (LIBS) combined with chemometrics. The information obtained from the LIBS spectra profiles with chemometrics analysis was promising for the construction of predictive models to identify healthy and infected plants. The major, macro- and microconstituents were relevant for differentiation of the sample conditions. The models were then applied to different inoculation times (from 1 to 8 months). The models were effective in the classification of 82-97% of the diseased samples with a 95% significance level. The novelty of this method was in the fingerprinting of healthy and diseased plants based on their organic and inorganic contents. 相似文献
88.
89.
90.
Mariana R. Almeida Rafael S. Alves Laura B. L. R. Nascimbem Rodrigo Stephani Ronei J. Poppi Luiz Fernando C. de Oliveira 《Analytical and bioanalytical chemistry》2010,397(7):2693-2701
Fourier transform Raman spectroscopy and chemometric tools have been used for exploratory analysis of pure corn and cassava starch samples and mixtures of both starches, as well as for the quantification of amylose content in corn and cassava starch samples. The exploratory analysis using principal component analysis shows that two natural groups of similar samples can be obtained, according to the amylose content, and consequently the botanical origins. The Raman band at 480 cm?1, assigned to the ring vibration of starches, has the major contribution to the separation of the corn and cassava starch samples. This region was used as a marker to identify the presence of starch in different samples, as well as to characterize amylose and amylopectin. Two calibration models were developed based on partial least squares regression involving pure corn and cassava, and a third model with both starch samples was also built; the results were compared with the results of the standard colorimetric method. The samples were separated into two groups of calibration and validation by employing the Kennard-Stone algorithm and the optimum number of latent variables was chosen by the root mean square error of cross-validation obtained from the calibration set by internal validation (leave one out). The performance of each model was evaluated by the root mean square errors of calibration and prediction, and the results obtained indicate that Fourier transform Raman spectroscopy can be used for rapid determination of apparent amylose in starch samples with prediction errors similar to those of the standard method. Figure
Raman spectroscopy has been successfully applied to the determination of the amylose content in cassava and corn starches by means of multivariate calibration analysis. 相似文献