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141.
The Raman spectra of N2O4 solutions in organic solvents have been recorded. The frequencies ofv
1,v
2, andv
3 bands of N2O4 increase with increasing solvent electron-donor properties. Especially large changes ofv
3 N-N stretching band have been observed (254.5 cm–1 in n-hexane, 276.5 cm–1 in 1,4-dioxane). The ab initio calculations have shown that the interaction between N2O4 and electron-donor molecules causes an increase of N-N and N-O stretching and O-N-O bending force constants of N2O4 in agreement with the results of Raman study. 相似文献
142.
A. Bączyński A. Kossakowski T. Marszałek 《Zeitschrift für Physik B Condensed Matter》1976,23(2):205-212
A quantum model of dye laser is given. To account for triplet losses a six levels model for the molecular system is assumed. The solution of generalized von Neumann equation in thermodynamical limit leads to a system of kinetic equations. Stationary solutions of this system are discussed. There are two distinct types of dependence of photon number versus pumping parameter. Beside a usual one, a new dependence characteristic for dye lasers only is present. In this case the definition of threshold should be revised. 相似文献
143.
When heated, the 3-hydroxybenzoates of Y, Sm and Eu(III) decompose in two steps. The hydrates first lose crystallization water and the anhydrous complexes are then transformed to oxides in air, and to mixtures of oxide and C in nitrogen atmosphere. When heated in air, the pentahydrates of La, Pr and Nd are dehydrated in two stages and the anhydrous complexes are then transformed to oxides; when heated in nitrogen, they are dehydrated in one step and then decomposed to mixtures of oxides and C.
Zusammenfassung Die 3-Hydroxybenzoate von Y, Sm und Eu(III) zersetzen sich beim Erhitzen in zwei Schritten. Die Hydrate verlieren zunächst Kristallwasser und die wasserfreien Komplexe werden in Luft in die Oxide und in Stickstoffatmosphäre in ein Gemisch des betreffenden Oxids und Kohlenstoff überführt. Beim Erhitzen in Luft werden die Pentahydrate von La, Pr und Nd in zwei Schritten dehydratisiert und die wasserfreien Komplexe in die Oxide überführt; beim Erhitzen in Stickstoff erfolgt dagegen die Dehydratisierung in nur einem Schritt und Endprodukt der Zersetzung ist ein Gemisch von Kohlenstoff und dem entsprechenden Oxid.
3- , . , — . , . , .相似文献
144.
Jacek Goworek Andrzej Dąbrowski Mieczysław Jaroniec Jerzy Garbacz 《Monatshefte für Chemie / Chemical Monthly》1982,113(8-9):925-932
The adsorption isotherms of methyl, ethyl,n-propyl andn-butyl acetates from benzene andn-heptane on silica gel have been measured at 298 K. A bilayer model of surface phase has been used to interpret these experimental data. It has been shown that the chain length of the hydrocarbon part of the ester and the solvent affinity to the adsorbent influence the structure of the surface phase. Moreover, this structure is also determined by energetic heterogeneity of the adsorbent surface.
Die Anwendung eines Zweischicht-Adsorptionsmodells zum Verständnis der Adsorption von Estern ausn-Heptan- und Benzollösungen auf Kieselgel
Zusammenfassung Es wurden die Adsorptionsisothermen der Methyl-, Ethyl-,n-Propyl undn-Butylacetate in Benzol undn-Heptanlösungen auf Kieselgel bei 298 K gemessen. Zur Interpretation der experimentellen Daten ist ein Zweischicht-Modell für die Oberflächenphase benutzt worden. Es wurde gezeigt, daß die Länge der Esterkohlenwasserstoffkette und die Aktivität des Lösungsmittels Einfluß auf die Struktur der Oberflächenform haben. Außerdem ist diese Struktur durch energetische Inhomogenität der Adsorbensoberfläche bestimmt.相似文献
145.
Sikorska-Iwan M. Mrozek Renata Ostasz A. Rzączyńska Z. 《Journal of Thermal Analysis and Calorimetry》2003,74(2):529-536
The 5-nitro-2-anthranilates of lanthanum(III), samarium(III), terbium(III), erbium(III) and lutetium(III) were obtained as
hydrates having 2.5 mol of water molecules per 1 mol of compound. The compounds are isostructural. The processes of dehydration
and rehydration were investigated. The first step of dehydration does not cause the change of crystal structure. The entire
dehydration gives anhydrous compounds with different structure than the structure of hydrates. However, the dehydration of
La, Sm, Tb and Er is reversible - the rehydration process gives the complexes having the same crystal structure as the initial
compounds. Only the anhydrous lutetium complex under the influence of moisture does not give the starting compound.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
146.
R. Rączka 《Czechoslovak Journal of Physics》1987,37(4):421-464
A gauge type model of quantum field theory for strong interactions based on a quinted of observed fields, namely the proton, neutron, , c and b baryon fields is proposed. Gauging the resulting global symmetry groupK= SU(3)×1
U(1)×2
U(1)×3
U(1) for matter fields, one obtains boson-fermion field theory with eleven gauge bosons. The analysis of admissible Higgs sector indicates that the Higgs multiple consists of one adjoint and two fundamental representationsSU(3) and three scalar representations of1
U(1),2
U(1) and3
U(1). The structure of the Higgs sector implies that the original symmetry group extends to the groupK×U(2). Breaking spontaneously the obtained field theory, one converts gauge bosons into the eleven massive vector bosons which can be identified with the observed , K*, ¯K*, , , J/ and Y vector mesons. The surviving global symmetry is isomorphic with the symmetry groupSU(2)×
0
U(1)× ×1
U(1)×2
U(1)×3
U(1) corresponding to the isospin, strangeness, baryon number, charm and beauty conservation observed in strong interactions. The surviving Higgs scalars have the same quantum numbers as , K, ¯K, , S, , , and b mesons. The model gives a newSU(3) classification scheme for baryons without charm and beauty in terms of triplets, sextets and 15-plets. These multiplets can be identified with the observed baryons; the scheme also includes the observed Z0 and Z1 baryons (the experimental evidence of which is, nevertheless, still weak). The model predicts the existence and the specific quantum numbers of new mesons and baryons with charm and beauty, and provides a very simple framework for the dibaryon analysis. Since all final physical fields are massive, this model is free from infrared divergences.Invited talk presented at the International Conference Selected Topics in Quantum Field Theory and Mathematical Physics, Bechyn, Czechoslovakia, June 23–27, 1986. 相似文献
147.
H. Zolądek 《Journal of statistical physics》1987,47(3-4):543-550
A standard random walk on a one-dimensional integer lattice is considered where the probability ofk self-intersections of a path =(0, (1),..., (n) is proportional toe
–k
. It is proven that for <0,n
–1/3(n) converges to a certain continuous random variable. For >0 the formulas are given for the asymptotic Westerwater velocity of a generic path and for the variance of the fluctuations about the asymptotic motion. 相似文献
148.
Fabian Grądzki 《Journal of solution chemistry》1988,17(12):1101-1118
A method of obtaining the potential of average force between two ions immersed in a polarizable hard sphere fluid is described. The ions and the solvent particles may have different hard sphere diameters. For large values of the reduced polarizability of the solvent particles, *, the potential of average force rises near contact much more steeply than the primitive model would permit and also has maxima and minima vanishing at larger distances, in semiquantitative agreement with the similar results of Patey and Valleau. The oscillating character of the potential of average force is due above all to the oscillations of the radial distribution function between the ion and polarizable hard sphere. 相似文献
149.
Complexes of yttrium(III) and lanthanides(III) with 4-hydroxy-3,5-dimethoxybenzoic (syringic) acid were obtained as solids
with metal to ligand mole ratio of 1: 3. The compounds were characterized by elemental analysis, IR spectroscopy, X-ray diffraction
patterns, solubility, and thermal studies. The complexes are sparingly soluble in water and stable at room temperature. Compounds
of light lanthanides (from La to Nd) are hydrated and they crystallize in a triclinic system. When heated, they lose water
molecules in one step and in the next step they decompose to oxides. Complexes of yttrium and other lanthanides are anhydrous
and crystallize in a monoclinic system. They are stable up to 300°C and then decompose to oxides. As the coordination number
of lanthanide ions is usually equal to 9 or 8, one can suppose that hydroxy or methoxy groups take part in the coordination
of these metal ions. 相似文献
150.
Kinetics of oxidation of Fe-Cr steel containing 25 wt.-percent Cr was studied as a function of temperature (1023–1173 K) for
up to 480 h in flowing air, which corresponds to SOFC cathode environment operating conditions. The oxidation process was
found to be a parabolic, suggesting that the diffusion of ionic defects in the scale is the slowest, rate determining step
and it occurs predominantly by short-circuit diffusion paths. Comparison of the determined activation energy of oxidation
of the studied steel with literature data indicates that at 1098–1173 K the chromia scale grows by the outward solid-state
diffusion of chromium interstitials, whereas at 1023–1098 K — through a significant contribution of counter-current oxygen/chromium
diffusion along Cr2O3 grain boundaries. The oxide scales were composed mainly of Cr2O3 with a continuous thin Mn1.5Cr1.5O4 spinel layer on top of the chromia scale. The oxidation test results on Fe-25Cr steel demonstrate the applicability of the
commercial type DIN 50049 stainless steel as interconnect for SOFC.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献