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21.
Christian Sunyach 《Potential Analysis》1994,3(2):171-187
Résumé Dans cet article j'étudie le comportement à l'infini des potentiels des chaînes de Markov sur
d
(d3) proches du mouvement brownien, tout spécialement le cas des marches aléatoires, ainsi que des critères de transience et de récurrence inspirés de la méthode utilisée.
We study the asymptotic behaviour of potentials of Markov chains on d (d3), closed to Brownian motion, and particularly the case of random walks. Following a similar approach, we give transience and recurrence criteria.相似文献
22.
Pavel Pyrih 《Potential Analysis》1994,3(3):273-281
We study the set of functions in quasi-analytic classes and the set of finely holomorphic functions. We show that no one of these two sets is contained in the other.LetI denote the set of complex functionsf: for which there exists a quasi-analytic classC{M
n} containingf. Let denote the set of complex functionsf: for which there exist a fine domainU containing the real line and a function
finely holomorphic onU satisfyingf(x)=
(x) for allx . The power of unique continuation is incomparable in these two cases (I\ is non-empty, \I is non-empty).Research supported by the grant No. 201/93/2174 of Czech Grant Agency and by the grant No. 354 of Charles University. 相似文献
23.
Jacqueline Ferrand 《Geometriae Dedicata》1996,61(1):103-120
This paper develops the theory of conformal invariants initiated inJ. Differential Geom
8 (1973), 487–510 for a Riemannian manifoldM with dimensionn2. We construct and study four conformally invariant functions M, M, M, M resp. depending on 4, 3 or 2 points onM, defined as extremal capacities for condensers associated with those points. These functions have similarities with the classical invariants onS
n
,R
n
orH
n
. Their properties, and especially their continuity, are efficient tools for solving some problems of conformal geometry in the large. 相似文献
24.
Let u(x, y) be defined in B
1×B
2 where B
1
m
and B
2
n
, and assume that u(x, ·) harmonic for every fixed x and u(·, y) is subharmonic for every fixed y. We show that if u(·, y) is, in addition, C
2 for each y then u is subharmonic in B
1×B
2 in both variables jointly. 相似文献
25.
Summary In a simply connected planar domainD the expected lifetime of conditioned Brownian motion may be viewed as a function on the set of hyperbolic geodesics for the domain. We show that each hyperbolic geodesic induces a decomposition ofD into disjoint subregions
and that the subregions are obtained in a natural way using Euclidean geometric quantities relating toD. The lifetime associated with on each
j
is then shown to be bounded by the product of the diameter of the smallest ball containing
j
and the diameter of the largest ball in
j
. Because this quantity is never larger than, and in general is much smaller than, the area of the largest ball in
j
it leads to finite lifetime estimates in a variety of domains of infinite area.Research of the first author was supported in part by NSF Grant DMS-9100811Research of the second author was supported in part by NSF Grant DMS-9105407 相似文献
26.
Compounds of general formulatrans-ArNi(PR3)2OAr' (R = Et, cyclohexyl; Ar = 2-MeC6H4, 2-FC6H4; Ar' = 4-FC6H4, 4-NO2C6H4) were synthesized by the reaction of Ar'OK with cationic nickel complexes generated by treatment of ArNi(PR3)2Cl with TlBF4. Syntheses of 4-fluorophenoxide complexes, ArNi(PR3)2OC6H4F-4, additionally give some quantities oftrans-[ArNi(PR3)2OC6H4F-4][HOC6H4F-4] adducts. Exchange reactions MeC6H4Ni(PEt3)2OC6H4F-4 + XC6H4OH 2-MeC6H4Ni(PEt3)2OC6H4X + 4-FC6H4OH were studied in THF. The equilibrium is shifted to the right as the acidity of ArOH increases. A linear relationship between lgK
eq and pK
a of XC6H4OH in DMSO was found. A conclusion concerning the strong polarization of the Ni-O bond was made on the basis of an analysis of the chemical shifts of fluorine atoms in 2-MeC6H4Ni(PEt3)2OC6H4F-4.Translated fromIvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2266–2271, November, 1995. 相似文献
27.
28.
The effect of geometry modifications of13C chemical shifts has been investigated in a small subset of molecules using both LO-INDO and Gaussian 70 (4–31) calculations. The Gaussian calculations, while known to give poor absolute shifts, compare well to the reparameterized semi-empirical INDO determinations in calculated shift changes. In virtually all cases the signs of the shift changes were found to be opposite to that of the changes in the calculated electronic energy. 相似文献
29.
Cerium phosphate nanoparticles with diameters of 10-180 nm were synthesized by a variety of solution techniques. X-ray diffraction (XRD) determined the crystalline phase(s) present in each sample. Population, shift, and spin-lattice relaxation 31P solid-state nuclear magnetic resonance (NMR) measurements accounted for all the 31P nuclei expected in each sample, and were able to distinguish between phosphorous nuclei in different environments and phases. Transmission electron microscopy (TEM) characterized the morphology and crystallinity of the powder samples as well as of the sintered compacts of the powders. In conjunction with TEM, energy-dispersive spectroscopy (EDS) provided a measure of the composition of the bulk intergranular regions within each CePO4 sample. The presence of an amorphous, phosphate-rich intergranular phase was found in those samples prepared by dissolution of ceria in H3PO4 under various conditions. 相似文献
30.
Helmut Pfitzner und Helmut Schweppe 《Fresenius' Journal of Analytical Chemistry》1974,268(5):337-342
Zusammenfassung In einer früheren Veröffentlichung [4] ist auf die Möglichkeit der chromatographischen Trennung strukturisomerer Metallchelate hingewiesen worden; sie soll hier ausführlicher dargestellt werden. Weiterhin wird die Trennung von 1:2-Mischkomplexen von Azofarbstoffen und von 1:2-Metallkomplex-Mischungen durch Dünnschicht-Chromatographie (DC) an Polyamid beschrieben. Unter bestimmten Voraussetzungen kann durch DC an Kieselgel zwischen 1:2-Metallkomplexfarbstoffen mit Sulfonsäureamid- bzw. Alkylsulfongruppen und solchen ohne diese Substituenten unterschieden werden. Die beschriebenen DC-Methoden ermöglichen bei richtiger Interpretation eine eindeutige Unterscheidung zwischen strukturisomeren Metallkomplexen der 1:1- und 1:2-Reihe, sowie Mischkomplexen und Komplexmischungen vom 1:2-Metall-chelattyp unsulfierter o,o31/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-Dihydroxyazoverbindungen.Symmetrische o,o31/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-Dihydroxyazoverbindungen, wie z.B. das 2,231/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-Dihydroxy-5,531/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dimethyl-azobenzol(7), sind geeignete Komplexbildner für Schwermetallkationen, um diese als farbige Chelate mit Hilfe der DC voneinander zu trennen. Strukturisomere sind wegen der Molekülsymmetrie ausgeschlossen, so daß die Ergebnisse eindeutig sind.
1:1 and 1:2 metal chelates of unsulphonated o,o31/xhuge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dihydroxyazo compounds: A thin-layer chromatographic investigation
In an earlier publication [4] the possibility of the Chromatographic separation of structurally isomeric metal chelates was mentioned; this is dealt with here in more detail. Further the separation of 1:2 mixed complexes from azo dyes and 1:2 metal-complex mixtures by thin-layer chromatography (TLC) on polyamide is described. In certain circumstances it is possible to distinguish between 1:2 metal-complex dyes with sulphonamide or alkylsulphonyl groups and those without these substituents by TLC on silica gel. The TCL methods described allow-when correctly interpreted-an unambiguous distinction between structurally isomeric metal complexes of the 1:1 and 1:2 series, and mixed complexes and mixtures of complexes of the 1:2 metal-chelate type of unsulphonated o,o31/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dihydroxyazo compounds.Symmetrical o,o31/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dihydroxyazo compounds, such as 2,231/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dihydroxy-5,531/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dimethylazobenzene(7), are suitable as complex-formers for heavy-metal ions, allowing the separation of the latter as their coloured chelates with aid of TLC. Structural isomers are excluded because of the molecular symmetry, so that the results are unambiguous.相似文献