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261.
The correlation between recent PAS results and the outcomes from mechanical testing of RPV model alloys are presented, here significant changes due to different chemical composition and different irradiation levels are observed. The influence of alloying elements to the microstructure degradation process following irradiation was identified by analysis of the mean-lifetime parameter, since an interesting interdependency of this parameter with hardness was observed. 相似文献
262.
We prove versions of James' weak compactness theorem for polynomials and symmetric multilinear forms of finite type. We also
show that a Banach spaceX is reflexive if and only if it admits and equivalent norm such that there existsx
0≠0 inX and a weak-*-open subsetA of the dual space, satisfying thatx
*⊗x
0 attains its numerical radius. for eachx
* inA.
The first and third author were supported in part by D.G.E.S., project no. BFM 2000-1467. The second author was partially
supported by Junta de Andalucía Grant FQM0199. 相似文献
263.
Lina M. Acosta Quintero Alirio Palma Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(4):346-357
A versatile synthetic method has been developed for the formation of variously substituted polycyclic pyrimidoazepine derivatives, formed by nucleophilic substitution reactions on the corresponding chloro‐substituted compounds; the reactions can be promoted either by conventional heating in basic solutions or by microwave heating in solvent‐free systems. Thus, (6RS)‐6,11‐dimethyl‐3,5,6,11‐tetrahydro‐4H‐benzo[b]pyrimido[5,4‐f]azepin‐4‐one, C14H15N3O, (I), was isolated from a solution containing (6RS)‐4‐chloro‐8‐hydroxy‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepine and benzene‐1,2‐diamine; (6RS)‐4‐butoxy‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐8‐ol, C18H23N3O2, (II), was formed by reaction of the corresponding 6‐chloro compound with butanol, and (RS)‐4‐dimethylamino‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐8‐ol, C16H20N4O, (III), was formed by reaction of the chloro analogue with alkaline dimethylformamide. (6RS)‐N‐Benzyl‐8‐methoxy‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐4‐amine, C22H24N4O, (IV), (6RS)‐N‐benzyl‐6‐methyl‐1,2,6,7‐tetrahydropyrimido[5′,4′:6,7]azepino[3,2,1‐hi]indol‐8‐amine, C22H22N4, (V), and (7RS)‐N‐benzyl‐7‐methyl‐2,3,7,8‐tetrahydro‐1H‐pyrimido[5′,4′:6,7]azepino[3,2,1‐ij]quinolin‐9‐amine, C23H24N4, (VI), were all formed by reaction of the corresponding chloro compounds with benzylamine under microwave irradiation. In each of compounds (I)–(IV) and (VI), the azepine ring adopts a conformation close to the boat form, with the C‐methyl group in a quasi‐equatorial site, whereas the corresponding ring in (V) adopts a conformation intermediate between the twist‐boat and twist‐chair forms, with the C‐methyl group in a quasi‐axial site. No two of the structures of (I)–(VI) exhibit the same range of intermolecular hydrogen bonds: different types of sheet are formed in each of (I), (II), (V) and (VI), and different types of chain in each of (III) and (IV). 相似文献
264.
Mario A. Macías Lina M. Acosta Carlos M. Sanabria Alirio Palma Pascal Roussel Gilles H. Gauthier Leopoldo Suescun 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(5):363-372
Tetrahydro‐1‐benzazepines have been described as potential antiparasitic drugs for the treatment of chagas disease and leishmaniasis, two of the most important so‐called `forgotten tropical diseases' affecting South and Central America, caused by Trypanosoma cruzi and Leishmania chagasi parasites, respectively. Continuing our extensive work describing the structural characteristics of some related compounds with interesting biological properties, the crystallographic features of three epoxy‐1‐benzazepines, namely (2SR,4RS)‐6,8‐dimethyl‐2‐(naphthalen‐1‐yl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, (1), (2SR,4RS)‐6,9‐dimethyl‐2‐(naphthalen‐1‐yl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, (2), and (2SR,4RS)‐8,9‐dimethyl‐2‐(naphthalen‐1‐yl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, (3), all C22H21NO, and two 1‐benzazepin‐4‐ols, namely 7‐fluoro‐cis‐2‐[(E)‐styryl]‐2,3,4,5‐tetrahydro‐1H‐1‐benzazepin‐4‐ol, C18H18FNO, (4), and 7‐fluoro‐cis‐2‐[(E)‐pent‐1‐enyl]‐2,3,4,5‐tetrahydro‐1H‐1‐benzazepin‐4‐ol, C15H20FNO, (5), are described. Some peculiarities in the crystallization behaviour were found, involving significant variations in the crystalline structures as a result of modest changes in the peripheral substituents in (1)–(3) and the occurrence of discrete disorder due to the molecular overlay of enantiomers with more than one conformation in (5). In particular, an interesting phase change on cooling was observed for compound (5), accompanied by an approximate fourfold increase of the unit‐cell volume and a change of the Z′ value from 1 to 4. This transition is a consequence of the partial ordering of the pentenyl chains in half of the molecules breaking half of the symmetry axes observed in the room‐temperature structure of (5). The structural assembly in all the title compounds is characterized by not only (N,O)—H…(O,N) hydrogen bonds, but also by unconventional C—H…O contacts, resulting in a wide diversity of packing. 相似文献
265.
R. Wolski I. Martel Ł. Standyło L. Acosta J. L. Aguado C. Angulo R. Berjillos J. P. Bolivar J. A. Duenas M. S. Golovkov T. Keutgen M. Mazzocco A. Padilla A. M. Sánchez-Benítez C. Signorini M. Romoli K. Rusek 《The European Physical Journal A - Hadrons and Nuclei》2011,47(9):1-8
Cross-sections for the production of 210Po nuclei in 6He + 206Pb collisions over the incident energy range 14-18MeV were measured by means of the activation technique and a radiochemical analysis. The elastic scattering at 18.0MeV was also measured providing a precise value for the 210Po production cross-section at this energy. The results are at variance with the earlier experimental data and rather in accord with the predictions of a density-dependent barrier penetration model for the fusion process. A proper treatment of beam energy distribution for the evaluation of the activation data is discussed. 相似文献
266.
Isaac Namioka conjectured that every nonreflexive Banach space can be renormed is such a way that, in the new norm, the set
of norm attaining functionals has an empty interior in the norm topology. We prove the rightness of this conjecture for spaces
containing an isomorphic copy of ℓ1. As a consequence, we prove also that the same result holds for a wide class of Banach spaces containing, for example, the
weakly compactly generated ones. 相似文献
267.
268.
Acosta Gloria Chapela Víctor Manuel 《Journal of inclusion phenomena and macrocyclic chemistry》1985,3(1):9-12
It was hypothesized that the formation of polypeptide bonds inside a lamellar superconducting compound such as 2H-TaS2 could enhance the superconducting transition temperature. The preparation of tantalum disulfide intercalated with polyglycine is described. The intercalated systems were characterized by powder X-ray diffraction and thermogravimetric analysis. Superconducting transition temperatures were also measured. The results show that the system 2H-TaS2/polyglycine does not have a more favourableT
cvalue than 2H-TaS2/glycine. 相似文献
269.
270.