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101.
Below T2 = 202 K, in the incommensurate phase, a Debye relaxation appears for c33; it can be attributed to a linear coupling between an acoustical mode and a phason. The relaxation time is τ = τ0/(T0?T) with τ0 = 6.2 x 10?12 sec deg and T0 = 200.9 K. The same phenomenon appears more weakly for c11. The c66 elastic constant has a double discontinuity around T1 = 169 K; this shows that in the vicinity of T1 there are two transitions, separated by a temperature interval of 3°. 相似文献
102.
103.
Benoit Kloeckner 《Transformation Groups》2006,11(2):185-194
The group of direct isometries of the hyperbolic space
This isometric action admits many differentiable compactifications into an action on the closed n-dimensional ball. We prove
that all such compactifications are topologically conjugate but not necessarily differentiably conjugate. We give the classifications
of real analytic and smooth compactifications. 相似文献
104.
A. Benoit M. Chapellier G. Chardin L. Dumoulin K. Eitel J. Gascon G. Gerbier C. Goldbach J. Jochum A. de Lesquen G. Nollez F. Pröbst W. Seidel 《Physics letters. [Part B]》2006
The ZEPLIN Collaboration has recently published its first result presenting a maximum sensitivity of 1.1×10−6 picobarn for a WIMP mass of ≈60 GeV. The analysis is based on a discrimination method using the different time distribution of scintillation light generated in electron recoil and nuclear recoil interactions. We show that the methodology followed both for the calibration of the ZEPLIN-I detector response and for the estimation of the discrimination power is not reliable enough to claim any background discrimination at the present stage. The ZEPLIN-I sensitivity appears then to be in the order of 10−3 picobarn, three orders of magnitude above the claimed 1.1×10−6 picobarn. 相似文献
105.
Desjardins Benoit 《偏微分方程通讯》2013,38(11-12):1667-1703
106.
Habauzit D Armengaud J Roig B Chopineau J 《Analytical and bioanalytical chemistry》2008,390(3):873-883
Estrogenic compounds are a class of pharmaceutical products harmful to animals and a cause of environmental damage. The biological
activity of these compounds is high since they have been designed to act at low concentrations. Thus, even at the low concentrations
found in the environment, they may produce deleterious effects on aquatic organisms as well as on humans, who might be contaminated
in a number of ways (via drinking water or contaminated food, for example). We used the property of these compounds to bind
a specific protein (estrogen receptor, ER) to develop a quantification method of these chemical entities. Estrogenic compound
detection was performed using ER dimerization properties monitored by surface plasmon resonance (SPR). The ligand-activated
ER dimer was detected by its interaction with a specific DNA consensus sequence estrogen response element. The concentration
and the nature of the estrogenic compounds modified the SPR signal and were characteristic of the ligand-dependent homodimerization
of ER. For 17β-estradiol, dimerization of ER was experimentally determined at an ER to 17β-estradiol ratio near 1:1. Estrogenic
compounds (17β-estradiol, estriol, estrone, ethynyl estradiol) activated the dimerization process at different concentration
levels, while some others (tamoxiphen, resveratrol, genistein, bisphenol A) did not seem to have any effects on it. We demonstrated
that this method allows the direct detection of 17β-estradiol at concentrations above 1.4 μg/L (5 nM). 相似文献
107.
Adrian J Pinacho DG Granier B Diserens JM Sánchez-Baeza F Marco MP 《Analytical and bioanalytical chemistry》2008,391(5):1703-1712
A multianalyte ELISA has been developed for the simultaneous determination of the most frequently used antibiotic families in the veterinary field following the typical planar microarray configuration, where the identity of the target analyte is encoded by its location in the detection platform (Master et al. in Drug Discovery Today 11:1007-1011, 2006). To accomplish this aim, two individual enzyme-linked immunosorbent assays for sulfonamide and fluoroquinolone antibiotics and an enzyme-linked receptor assay for ss-lactam antibiotics have been combined. The strategy uses microplates coated with the corresponding haptenized proteins in specific sections of the microplate. The samples are mixed with a cocktail containing the bioreagents, and distributed in the wells of the microplate. Identification of the antibiotic present in a particular sample is consequently accomplished by detecting a positive response on the corresponding microplate section. Since the bioreceptors used show a wide recognition of the congeners of each antibiotic family, the multianalyte method is able to detect more than 25 different antibiotics from the three most important antibiotic families. The detectability reached in full-fat milk samples is below the European maximum residue limits. The accuracy and reliability of this multiplexed bioanalytical method have been demonstrated by analyzing blind spiked samples. 相似文献
108.
Boulinguiez B Le Cloirec P Wolbert D 《Langmuir : the ACS journal of surfaces and colloids》2008,24(13):6420-6424
The selection of a proper sorbent for a given application is a complex problem. The design and efficiency of adsorption processes require an equilibrium adsorption model. Linear transformation is one of the methods available to estimate the adjustable parameters of isotherm models but possesses limitations compared to nonlinear regressions. A different approach to calculate predicted equilibrium isotherm values leading to an alternative nonlinear regression is presented in this paper and compared with usual regression methods. Adsorption isotherm data of gaseous THT onto three activated carbon materials constitute an experimental basis for the discussion. Assessment of the goodness-of-fit of the Langmuir model is supported by different selected test functions. The new nonlinear approach did not obtain the best results for each test function, but raises questions about the inherent combined error in regression procedures. 相似文献
109.
Coasne B Di Renzo F Galarneau A Pellenq RJ 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7285-7293
This paper reports a molecular simulation study on the adsorption of simple fluids (argon at 77 K) on hydroxylated silica surfaces and nanopores. The effect of surface chemistry is addressed by considering substrates with either partially or fully hydroxylated surfaces. We also investigate the effect of pore shape on adsorption and capillary condensation by comparing the results for cylindrical and hexagonal nanopores having equivalent sections (i.e., equal section areas). Due to the increase in the polarity of the surface with the density of OH groups, the adsorbed amounts for fully hydroxylated surfaces are found to be larger than those for partially hydroxylated surfaces. Both the adsorption isotherms for the cylindrical and hexagonal pores conform to the typical behavior observed in the experiments for adsorption/condensation in cylindrical nanopores MCM-41. Capillary condensation occurs through an irreversible discontinuous transition between the partially filled and the completely filled configurations, while evaporation occurs through the displacement at equilibrium of a hemispherical meniscus along the pore axis. Our data are also used to discuss the effect of surface chemistry and pore shape on the BET method. The BET surface for fully hydroxylated surfaces is much larger (by 10-20%) than the true geometrical surface. In contrast, the BET surface significantly underestimates the true surface when partially hydroxylated surfaces are considered. These results suggest that the surface chemistry and the choice of the system adsorbate/adsorbent is crucial in determining the surface area of solids using the BET method. 相似文献
110.
A calix[6]arene has been selectively functionalized by three different groups at the large rim. The strategy relies on the hostguest recognition chemistry of a biomimetic metal complex at the small rim (so-called "funnel complex") and the Huisgen cycloaddition. The intramolecular thermal reaction proceeds with a high efficiency, chemio- and regioselectivity, allowing the monofunctionalization of one aromatic unit among three. Thanks to the high yield and selectivity of the reaction, it can be applied successively twice on the same compound, which opens the route for inherently chiral calix[6]arenes. This methodology not only is of wide potential for obtaining and exploiting calix[6]arenes that are dissymmetrized at the large rim, but also stands as an exemplary strategy for the selective appending of a functional group on a host platform. 相似文献