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741.
Soraru Gian Domenico Babonneau Florence Gervais Christel Dallabona Nicola 《Journal of Sol-Gel Science and Technology》2000,18(1):11-19
A new sol-gel route, without any external water addition, for the preparation of hybrid RSiO1.5/B2O3 gels (R = Me, Et, Vi) is reported. The gels are easily synthesized by reacting B(OH)3 with the liquid silicon alkoxide. The gels have been characterized mainly by FT-IR and 11B MAS NMR spectroscopy. The results show that this new sol-gel process allows the formation of a homogeneous borosilicate gel in which trigonal BO3 units are incorporated into the siloxane network via B—O—Si bonds. 相似文献
742.
G. C. Barbarino P. Bernardini S. Bussino D. Campana G. De Cataldo M. De Vincenzi A. Di Credico P. Fusco N. Giglietto A. Grillo F. Guarino C. Gustavino E. Lamanna A. Lauro G. Mancarella A. Margiotta D. Martello M. M. Mazziotta S. Mikheyev G. Osteria A. Rain U. Rubizzo E. Scapparone P. Spinelli M. Spurio A. Surdo 《Nuclear Physics B - Proceedings Supplements》1999,70(1-3)
The project of a large underground experiment, NOE (Neutrino Oscillation Experiment), composed by modules of scintillating fiber calorimeter interleaved with TRD modules, total weight 6.7 ktons, is presented. This apparatus has been optimized for long baseline neutrino oscillation studies, in particular to be sensitive in the region of sin2 2θ and Δm2 suggested by the atmospheric neutrino anomaly (fig. 3). 相似文献
743.
A. Biancalana E. Campani G. Di Domenico G. Gorini A. Iacoponi G. Masetti 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1999,55(14):2883
In this work we present the first direct observation of a 220 cm−1 progression in the absorption spectrum of trans-azobenzene in the vapour phase. The mode at 220 cm−1 is essential to explain both the electronic absorption spectrum and the Raman excitation profiles of the most intense Raman bands of trans-azobenzene in the 1000–1600 cm−1 shift range. Our data in the vapour phase assure that this frequency pertains to an internal molecular mode. 相似文献
744.
Domenico Larobina Marino Lavorgna Giuseppe Mensitieri Pellegrino Musto Alain Vautrin 《Macromolecular Symposia》2007,247(1):11-20
In-situ, time-resolved FTIR spectroscopy along with gravimetric analysis have been used to investigate water sorption and transport in several glassy polymeric matrices, characterized by different levels of interaction with water, as well as on polymer-silica hybrids. This technique has also been coupled to a dynamical-mechanical analyser to gather information on the water sorption kinetics and thermodynamics in a polymer sample submitted to stretching deformation and load. Results have been modelled by coupling the mass balance and momentum balance, using a theoretical approach developed for elastic matrices and low sorbed amounts by Larché and Cahn. 相似文献
745.
the processing behaviour and physical properties of polypropylene/flame retardant blends were investigated in order to evaluate their use in the wire-coating process. In particular, the need of flame retardancy, suitable melt processability and good mechanical properties of blends was taken into account. Three types of halogen free flame retardants were chosen and were melt blended to the polypropylene matrix. Blends properties were analysed by rheological, mechanical, and thermal characterization including flame retardancy tests. The wire coating process was also performed by a laboratory wire coating apparatus. The results demonstrated that some of the blends are suitable for the purpose of flame retardancy of electrical household wires as an alternative to PVC. 相似文献
746.
Adriana Caracciolo Gianmarco Vanuzzo Nadia Balucani Domenico Stranges Silvia Tanteri Carlo Cavallotti Piergiorgio Casavecchia 《化学物理学报》2019,32(1):113-122
详细了解O(~3P)与不饱和烃的多通道燃烧反应机理需要鉴定所有主要反应产物、确定分支比、评估三重态与单重态势能面之间的系间窜跃.将交叉分子束实验、软电离、质谱、飞行时间分析,以及高级从头算计算三重态/单线态势能面,RRKM/Master方程计算支化比包括系间窜跃,均可以获得最佳效果.最近已经证明这些方法对于含有两个或三个碳原子的最简单的不饱和烃(炔烃,烯烃,二烯)和O(~3P)反应是成功的.本文通过交叉分子束与理论相结合的方法研究O(~3P)和含有四个C原子的二烯类化合物,1,2-丁二烯(甲基芳烃)的反应,探索产物分布、分支比和系间窜跃如何随着分子复杂性的增加而变化,即从O(~3P)和丙二烯反应到O(~3P)1,2-丁二烯的反应变化.尤其关注了最重要的导致链终止的主导分子通道(即形成丙烯+CO(分支≥0.5)和亚乙基+乙烯酮(分支比≥0.15))与导致链传递的自由基形成通道进行对比(分支比≥0.35). 相似文献
747.
V. Cuomo P. Di Girolamo R. V. Gagliardi G. Pappalardo N. Spinelli R. Velotta A. Boselli V. Berardi B. Bartoli 《Il Nuovo Cimento C》1995,18(2):209-222
Summary The possibility of performing atmospheric-transmissivity measurements by lidar is considered. In the present paper two distinct
methods have been successfully applied. The first one is based on the detection of the Raman return from molecular nitrogen.
An alternative method is based on the simultaneous detection of the elastic and N2 Raman returns. Measurements based on both techniques are discussed in detail, the second technique producing more accurate
results. Through this technique an estimation of the ?ngstr?m coefficient can also be obtained. 相似文献
748.
In this paper we give a decision procedure for a topological syllogistic, denoted ?2,∞, involving, besides the standard Boolean set operators (∩, ∩, ′ (set complementation)) and predicates ( ? (membership), = (equality)), also the Kuratowski closure operator, continuous and closed maps with the notion of direct and inverse images, surjectivity and injectivity, as well as point evaluation, the singleton operator {·}, a predicate for comparing the cardinalities of two given sets, and a predicate expressing that a given set is topologically connected. Several examples are also discussed. © 1994 John Wiley & Sons, Inc. 相似文献
749.
In this paper, contact metric manifolds whose characteristic vector field ξ is a harmonic vector field are called H-contact manifolds. We show that a (2n+1)-dimensional contact metric manifold is an H-contact manifold if and only if ξ is an eigenvector of the Ricci operator (J.C. González-Dávila and L. Vanhecke [J. Geom. 72 (2001) 65–76] proved this result for n=1). Consequently, the class of H-contact manifolds is very large. Moreover, we give some application about the topology of a compact H-contact manifold. 相似文献
750.
R. Spinelli de Carvalho John G. Crookes 《The Journal of the Operational Research Society》1976,27(1):31-40
Cellular simulation, a method of organizing simulation models to improve experimental efficiency, is described and shown to have the further advantages of reconciling the event based approach with the activity approach to simulation modelling and to have implication for modelling large systems. 相似文献