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21.
In terms of the Avrami equation, the effects of selected organic pigments on the kinetic parameters of the isothermal crystallization of coloured polyamide 6 were examined in the temperature range 468–478 K. It was found that B Blue and BB Red are active nucleating agents, which is acribed to their crystalline structure. G Orange slightly accelerates the crystallization of PA 6 at lower temperatures and concentrations, whereas in other conditions its effect is the opposite.The isothermal data were confirmed by the results of non-isothermal crystallization. The degree of supercooling corresponding to the peak of the DSC curve was the measured feature in this case.It was found that B Blue and BB Red reduce the free energy of formation of criticalsize nuclei by 20 and 12%, respectively, which is reflected in the rates of crystallization.
This work was supported by the Polish Academy of Science, goal 01.14. 相似文献
Zusammenfassung Mit Hilfe der Avrami Gleichung wurde der Einfluß einiger ausgewählter organischer Pigmente auf die kinetischen Parameter der isothermen Kristallisation gefärbter Polyamide 6 im Temperaturbereich 468–478 K untersucht. B Blue und BB Red erwiesen sich als aktive Keimbilder, was mit Hilfe ihrer kristallinen Struktur erklärt werden kann. Bei niedrigeren Temperaturen und geringeren Konzentrationen wird die Kristallisation von PA 6 durch G Orange leicht beschleunigt, unter anderen Bedingungen kann das Gegenteil beobachtet werden. Die isothermen Daten wurden durch die Ergebnisse bei nichtisothermer Kristallisation bekräftigt. In diesem Falle wurde das dem DSC Peak entsprechende Maß an Unterkühlung untersucht. Es wurde gefunden, daß B Blue und BB Red die freie Energie zur Bildung von Keimen kritischer Größe um 20 bzw. 12% herabsetzen, was sich in den Kristallisationsgeschwindigkeiten widerspiegelt.
, -6 468–478 . , , . , . . . , , , 20 12%, .
This work was supported by the Polish Academy of Science, goal 01.14. 相似文献
22.
W. Kołos 《Chemical physics letters》1976,39(3):416-417
The interaction energy between two hydrogen atoms in the D and D′ 1Πu states of the hydrogen molecule has been calculated for large internuclear distances (12 ? R ? 25 bohr). The variational method and a very flexible trial wave-function were used. The results indicate that for the states under consideration the Rayleigh-Schrödinger perturbation theory with the multipole expansion of the interaction hamiltonian gives reliable results only for R > 25 bohr i.e. in the region where the interaction energies are practically negligible. 相似文献
23.
24.
A. Małecki A. Małecka R. Gajerski B. Prochowska-Klisch A. Podgórecka 《Journal of Thermal Analysis and Calorimetry》1988,34(1):203-209
The mechanism of thermal decomposition of Co(NO3)2 · 2H2O was found to involve stages in which Co(NO3)3 and Co2O3 · H2O are formed both of which decompose to Co3O4. During the process, the total cobalt enters the +3 oxidation state, which is consistent with the results reported by Mehandjiev [2].
Zusammenfassung Es wurde gefunden, daß der Zersetzungsmechanismus von Co(NO3)2 · 2H2O Schritte umfaßt, bei denen Co(NO3)3 sowie Co2O3 · H2O gebildet werden, beides weiterzerfallend zu Co3O4. Während des Vorganges erreicht das Gesamtkobalt die Oxidationsstufe +3, was mit Ergebnissen von Mehandjiev übereinstimmt [2].
, , CO3O4. , .相似文献
25.
It is shown that double-orthogonal sets (diamonds) in Minkowski space form an orthomodular complete lattice. Connection with empirical logic of Randall and Foulis is discussed. 相似文献
26.
A. Bączyński A. Kossakowski T. Marszałek 《Zeitschrift für Physik B Condensed Matter》1977,26(1):93-95
The expression for losses due to triplet states in dye laser considered as a six-level system is given. It is shown that triplet losses depend on pumping parameters and photon number. Depending on molecular and cavity parameters two different behaviours of dye lasers are expected. Physical conditions are discussed in which triplet losses as well as photon number undergo a jump at the threshold. 相似文献
27.
Rodríguez-Cea A de la Campa MR Sanz-Medel A 《Analytical and bioanalytical chemistry》2005,381(2):388-393
Cytochromes P-450 are members of a superfamily of hemoproteins involved in the oxidative metabolism of various physiological and xenobiotic compounds in eukaryotes and prokaryotes. The multiplicity of this group of enzymes has been widely studied by chromatographic techniques, mainly high-performance liquid chromatography (HPLC). Because these enzymes are membrane-bound proteins, sample preparation for chromatographic separation of P-450 enzymes requires a solubilization step. The sample-preparation procedures are critical, because detergents affect not only the efficiency of protein solubilization but also their further chromatographic resolution. Trout liver microsomes have been taken here as a model sample to investigate iron speciation in cytochrome P-450. Trouts were treated intraperitoneally with -naphthoflavone, a potent inducer of some P-450 enzymes, and a microsomal suspension containing 7.4±0.1 nmol mL–1 P-450 enzymes was obtained by ultracentrifugation. Lubrol PX was selected as detergent for solubilization, resulting in about 90% solubilization recovery. The solubilized cytochromes P-450 were further separated by AE–FPLC, with UV detection, or coupled to ICP–MS with an octapole reaction system, ICP–(ORS)MS (monitoring Fe signals at masses 54, 56, and 57). A sampling procedure and chromatographic conditions are developed and were successfully applied to iron speciation in trout liver P-450 enzymes. ICP–(ORS)MS detection of P-450 enzymes is Fe-specific and so will give accurate information on the prosthetic group of the protein, which can constitute an advantageous alternative to classical methods for detection of these hemoproteins. 相似文献
28.
Differencies between the mechanism ofn-hexane and benzene adsorption on active carbon were investigated on the ground of kinetic measurements. As it has been stated, the kinetic measurements show fundamental differencies between the mechanism of adsorption in spite of analogy existing in the state of adsorption equilibrium. Within the range investigated, only the adsorption ofn-hexane follows the model of volume filling of micropores. Existence of those differencies is also confirmed by measurements of effective diffusion coefficient values as well as changes of activation energy of the diffusion—adsorption process.
Anwendung kinetischer Untersuchungen zur Interpretation des Adsorptionsverhaltens vonn-Hexan und Benzol an Aktivkohle
Zusammenfassung Mittels kinetischer Messungen untersuchte man die Unterschiede im Mechanismus des Adsorptionsverlaufes vonn-Hexan und Benzol an Aktivkohle. Man stellte fest, daß trotz der Analogie im Adsorptionsgleichgewichtszustand die kinetischen Messungen auf prinzipielle Unterschiede im Adsorptionsmechanismus hinweisen. Im untersuchten Bereich verläuft nur die Adsorption vonn-Hexane nach dem Modell der Mikroporenvolumenausfüllung. Die auftretenden Unterschiede wurden auch durch die Berechnungen der Werte der effektiven Diffusionskoeffizienten sowie Änderungen der Aktivierungsenergie des Diffusions-Adsorptionsprozesses bestätigt.相似文献
29.
Cyrański MK Howard ST Chodkiewicz ML 《Chemical communications (Cambridge, England)》2004,(21):2458-2459
Various models applied to DFT structures and energies of 2-D and 3-D aromatic molecules shed new light on the effects of strain and aromaticity in these systems. The cyclic pi electron delocalisation does not stabilize the fullerene C60 formation; and 5-6 and 6-6 CC bonds have near-identical bond stretch potentials. 相似文献
30.
The kinetics of base hydrolysis of the trans-[Cr(NH3)2(NCS)4]– anion follows the rate law: -d[complex]/dt = k
0 + k
1[OH–] (50–70 °C, [OH–] = 0.1–1.9 M and = 2.0 M). The specific salt effect has been investigated for eight aqueous media: NaCl, NaBr, NaI, NaClO4, KCl, KBr, CsCl and CsBr. The alkali-independent path (k
0) does not show any specific effect of inert electrolyte ions, the activation parameters: H
= 113.5 ± 0.4 kJ mol–1 and S
= 24.1 ± 1.3 J mol–1 K–1 are interpreted in the frame of a dissociative interchange mechanism (I
d). For the alkali-dependent path (k
1) the specific salt effect is observed for cations of the inert electrolyte, showing an important role for ion-pair formation between the cations and reagent complex anion in the activation process. A linear correlation between lnk
1 and lnK
0 (K
0 – ion-pair formation constant) has been found for the cations studied. The dissociative, via conjugate base, mechanism (D
CB) has been proposed for the alkali-dependent path. 相似文献