全文获取类型
收费全文 | 242篇 |
免费 | 5篇 |
专业分类
化学 | 141篇 |
力学 | 21篇 |
数学 | 28篇 |
物理学 | 57篇 |
出版年
2022年 | 6篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 2篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 11篇 |
2011年 | 14篇 |
2010年 | 5篇 |
2009年 | 14篇 |
2008年 | 17篇 |
2007年 | 10篇 |
2006年 | 18篇 |
2005年 | 9篇 |
2004年 | 16篇 |
2003年 | 7篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1960年 | 1篇 |
1955年 | 1篇 |
1939年 | 1篇 |
1938年 | 1篇 |
1935年 | 3篇 |
1933年 | 1篇 |
1932年 | 1篇 |
1931年 | 1篇 |
1880年 | 1篇 |
排序方式: 共有247条查询结果,搜索用时 46 毫秒
21.
Methods for determining the heat content E
*/A of hot nuclei formed in energetic nuclear reactions are discussed. The primary factors involved in converting raw data into
thermal physics distributions include: 1) design of the detector array, 2) constraints imposed by the physics of the reaction
mechanism, and 3) assumptions involved in converting the filtered data into E
*/A. The two primary sources of uncertainty in the calorimetry are the elimination of nonequilibrium emissions from the event
components and accounting for the contribution of neutron emission to the excitation energy sum. 相似文献
22.
23.
24.
Tullio Viola 《Annali di Matematica Pura ed Applicata》1960,49(1):367-373
Sunto Si disente criticamente il detto postulato, con particolare riguardo al problema della sua compatibilità entro il sistema
ipotetico — deduttivo dell'Hilbert.
A Giovanni Sansone nel suo 70mo compleanno. 相似文献
25.
Tullio Viola 《Annali di Matematica Pura ed Applicata》1955,39(1):381-391
Sunto Si studia una definizione del tutto generale di funzione quasi continua; si enuncia e dimostra poi un teorema, concettualmente
nuovo, per le successioni di funzioni che sono quasi continue nel senso generale studiato.
A Mauro Picone nel suo 70mo compleanno.
Lavoro eseguito presso l'Istituto Nazionale per le Applicazioni del Calcolo. 相似文献
26.
Summary The problem of two symmetric arc cracks lying between a rigid circular inclusion embedded in an infinite matrix under biaxial loading at infinity is considered. By using the complex variable tecnique, the boundary value problem is solved and stress and displacement components are calculated along the inclusion boundary. Moreover, investigating the local stress field, a stress criterion, already proposed by authors, allowing either the crack extension at the interface or its deviation into the matrix to be taken into account, is applied to study the fracture response of the elastic system. The critical applied loads as well as the angle of the incipient crack extension are expressed in terms of the central angle subtended by the crack arcs.Finally the biaxial load effects are graphically shown and discussed.
Financial support of the National Research Council (C.N.R.) (research contribution N. 79.01625.07) is gratefully acknowledged. 相似文献
Sommario Si considera il problema piano di due «craks» simmetrici all'interfaccia tra una inclusione circolare rigida e la circostante matrice, in regime di carico biassiale. Facendo uso della tecnica delle variabili complesse, viene risolto il problema dei valori al contorno, ricavando altresi le espressioni delle tensioni e degli spostamenti lungo il contorno dell'inclusione. Inoltre, applicando un criterio tensionale, già proposto dagli autori, che consente di studiare sia la estensione del crack all'interfaccia che la sua deviazione nella matrice, si analizza la risposta del sistema considerato. I valori critici dei carichi applicati, nonchè l'angolo di frattura, risultano espressi in funzione dell'angolo al centro sotteso dai cracks.Infine, vengono illustrati graficamente e discussi gli effetti del carico laterale.
Financial support of the National Research Council (C.N.R.) (research contribution N. 79.01625.07) is gratefully acknowledged. 相似文献
27.
We demonstrate the advantages of randomization in coherent quantum dynamical control. For systems which are either time-varying or require decoupling cycles involving a large number of operations, we find that simple randomized protocols offer superior convergence and stability as compared to deterministic counterparts. In addition, we show how randomization may allow us to outperform purely deterministic schemes at long times, including combinatorial and concatenated methods. General criteria for optimally interpolating between deterministic and stochastic design are proposed and illustrated in explicit decoupling scenarios relevant to quantum information storage. 相似文献
28.
We give an example of an exact, stably finite, simple, separable C*-algebra D which is not isomorphic to its opposite algebra. Moreover, D has the following additional properties. It is stably finite, approximately divisible, has real rank zero and stable rank one, has a unique tracial state, and the order on projections over D is determined by traces. It also absorbs the Jiang-Su algebra Z, and in fact absorbs the 3∞ UHF algebra. We can also explicitly compute the K-theory of D, namely ${K_0 (D) \cong {\mathbb{Z}} [ \tfrac{1}{3}]}$ with the standard order, and K 1 (D) = 0, as well as the Cuntz semigroup of D, namely ${W (D) \cong {\mathbb{Z}} [ \tfrac{1}{3} ]_{+} \sqcup (0, \infty).}$ 相似文献
29.
30.
Alessandro Marzani Erasmo Viola Francesco Lanza di Scalea 《Journal of sound and vibration》2008,318(3):488-505
A semi-analytical finite element (SAFE) method is presented for analyzing the wave propagation in viscoelastic axisymmetric waveguides. The approach extends a recent study presented by the authors, in which the general SAFE method was extended to account for material damping. The formulation presented in this paper uses the cylindrical coordinates to reduce the finite element discretization over the waveguide cross-section to a mono-dimensional mesh. The algorithm is validated by comparing the dispersion results with viscoelastic cases for which a Superposition of Partial Bulk Waves solution is known. The formulation accurately predicts dispersion properties and does not show any missing root. Applications to viscoelastic axisymmetric waveguides with varying mechanical and geometrical properties are presented. 相似文献