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101.
Suppose A,B and C are the bounded linear operators on a Hilbert space H, when A has a generalized inverse A- such that (AA-)*=AA- and B has a generalized inverse B- such that (B-B)*=B-B,the general characteristic forms for the critical points of the map Fp:X→‖AXB-C‖pp(1
p=2. Similarly, the same question has been discussed for several operators. 相似文献
102.
Consider a second order divergence form elliptic operator L with complex bounded measurable coefficients. In general, operators based on L, such as the Riesz transform or square function, may lie beyond the scope of the Calderón–Zygmund theory. They need not be
bounded in the classical Hardy, BMO and even some L
p
spaces. In this work we develop a theory of Hardy and BMO spaces associated to L, which includes, in particular, a molecular decomposition, maximal and square function characterizations, duality of Hardy
and BMO spaces, and a John–Nirenberg inequality.
S. Hofmann was supported by the National Science Foundation. 相似文献
103.
Jean-Daniel Boissonnat Leonidas J. Guibas Steve Y. Oudot 《Discrete and Computational Geometry》2009,42(1):37-70
It is a well-established fact that the witness complex is closely related to the restricted Delaunay triangulation in low
dimensions. Specifically, it has been proved that the witness complex coincides with the restricted Delaunay triangulation
on curves, and is still a subset of it on surfaces, under mild sampling conditions. In this paper, we prove that these results
do not extend to higher-dimensional manifolds, even under strong sampling conditions such as uniform point density. On the
positive side, we show how the sets of witnesses and landmarks can be enriched, so that the nice relations that exist between
restricted Delaunay triangulation and witness complex hold on higher-dimensional manifolds as well. We derive from our structural
results an algorithm that reconstructs manifolds of any arbitrary dimension or co-dimension at different scales. The algorithm
combines a farthest-point refinement scheme with a vertex pumping strategy. It is very simple conceptually, and it does not
require the input point sample to be sparse. Its running time is bounded by c(d)n
2, where n is the size of the input point cloud, and c(d) is a constant depending solely (yet exponentially) on the dimension d of the ambient space. Although this running time makes our reconstruction algorithm rather theoretical, recent work has shown
that a variant of our approach can be made tractable in arbitrary dimensions, by building upon the results of this paper.
This work was done while S.Y. Oudot was a post-doctoral fellow at Stanford University. His email there is no longer valid. 相似文献
104.
Problems of matching have long been studied in the operations research literature (assignment problem, secretary problem, stable marriage problem). All of these consider a centralized mechanism whereby a single decision maker chooses a complete matching which optimizes some criterion. This paper analyzes a more realistic scenario in which members of the two groups (buyers–sellers, employers–workers, males–females) randomly meet each other in pairs (interviews, dates) over time and form couples if there is mutual agreement to do so. We assume members of each group have common preferences over members of the other group. Generalizing an earlier model of Alpern and Reyniers [Alpern, S., Reyniers, D.J., 2005. Strategic mating with common preferences. J. Theor. Biol. 237, 337–354], we assume that one group (called males) is r times larger than the other, r?1. Thus all females, but only 1/r of the males, end up matched. Unmatched males have negative utility -c. We analyze equilibria of this matching game, depending on the parameters r and c. In a region of (r,c) space with multiple equilibria, we compare these, and analyze their ‘efficiency’ in several respects. This analysis should prove useful for designers of matching mechanisms who have some control over the sex ratio (e.g. by capping numbers of males at a ‘singles event’or by having ‘ladies free’ nights) or the nonmating cost c (e.g. tax benefits to married couples). 相似文献
105.
Felipe Cucker Steve Smale Ding-Xuan Zhou 《Foundations of Computational Mathematics》2004,4(3):315-343
We describe a model for the evolution of the languages used by the agents of a
society. Our main result proves convergence of these languages to a common
one under certain conditions. A few special cases are elaborated in more
depth. 相似文献
106.
We give asymptotic formulas for the multiplicities of weights and irreducible summands in high-tensor powers Vλ⊗N of an irreducible representation Vλ of a compact connected Lie group G. The weights are allowed to depend on N, and we obtain several regimes of pointwise asymptotics, ranging from a central limit region to a large deviations region. We use a complex steepest descent method that applies to general asymptotic counting problems for lattice paths with steps in a convex polytope. 相似文献
107.
Zhanar Berikkyzy Steve Butler Jay Cummings Kristin Heysse Paul Horn Ruth Luo Brent Moran 《Discrete Mathematics》2018,341(2):497-507
Consider the following process on a simple graph without isolated vertices: order the edges randomly and keep an edge if and only if it contains a vertex which is not contained in some preceding edge. The resulting set of edges forms a spanning forest of the graph.The probability of obtaining components in this process for complete bipartite graphs is determined as well as a formula for the expected number of components in any graph. A generic recurrence and some additional basic properties are discussed. 相似文献
108.
Professor A. Siginer 《Rheologica Acta》1991,30(5):447-473
Superposition of oscillatory shear imposed from the boundary and through pressure gradient oscillations and simple shear is investigated. The integral fluid with fading memory shows flow enhancement effects due to the nonlinear structure. Closed-form expressions for the change in the mass transport rate are given at the lowest significant order in the perturbation algorithm. The elasticity of the liquid plays as important a role in determining the enhancement as does the shear dependent viscosity. Coupling of shear thinning and elasticity may produce sharp increases in the flow rate. The interaction of oscillatory shear components may generate a steady flow, either longitudinal or orthogonal, resulting in increases in flow rates akin to resonance, and due to frequency cancellation, even in the absence of a mean gradient. An algorithm to determine the constitutive functions of the integral fluid of order three is outlined.Nomenclature
A
n
Rivlin-Ericksen tensor of order .
-
A
k
Non-oscillatory component of the first order linear viscoelastic oscillatory velocity field induced by the kth wave in the pressure gradient
-
d
Half the gap between the plates
-
e
x, e
z
Unit vectors in the longitudinal and orthogonal directions, respectively
-
G(s)
Relaxation modulus
-
G
History of the deformation
-
Stress response functional
-
I()
Enhancement defined as the ratio of the frequency dependent part of the discharge to the frequencyindependent part of it at the third order
-
I
*()
Enhancement defined as the ratio of the increase in discharge due to oscillations to the total discharge without the oscillations
-
k
Power index in the relaxation modulus G(s)
-
k
i
–1
Relaxation times in the Maxwell representation of the quadratic shear relaxation modulus (s
1, s
2)
-
m
i
–1, n
i
–1
Relaxation times in the Maxwell representations of the constitutive functions 1(s
1,s
2,s
3) and 4 (s
1, s
2,s
3), respectively
-
P
Constant longitudinal pressure gradient
-
p
Pressure field
-
mx
,(3)
nz
,(3)
Mean volume transport rates at the third order in the longitudinal and orthogonal directions, respectively
- 0,(3), 1,(3)
Frequency independent and dependent volume transport rates, respectively, at the third order
-
s = t-
Difference between present and past times t and 相似文献
109.
杨光崇 《应用数学和力学(英文版)》2002,23(3):341-349
IntroductionInvestigatingthefollowingboundaryprobleminordinarydifferentialequation :¨x+f(t,x(t) ) =0 ,a<t<b,αx(a) -β x(a) =0 ,γx(b) +δ x(b) =0 ,( 1 )whereα ,β,γ ,δ≥ 0 ,Δ=(b-a)αγ+αδ+ βγ>0 .f(t,s)maybesingularint =a ,b.Ithasbeendirectlyverifiedthatx(t)isthesolutionof( 1 )inC2 [a ,b]ifandonlyifx(… 相似文献
110.
STATISTIC MODELING OF THE CREEP BEHAVIOR OF METAL MATRIX COMPOSITES BASED ON FINITE ELEMENT ANALYSIS 总被引:1,自引:0,他引:1
岳珠峰 《应用数学和力学(英文版)》2002,23(4):421-434
IntroductionThecreepbehaviorofshortfiberreinforceMetalMatrixComposites (MMCs)dependsonthefollowingfactors,suchasthecreeppropertyofthematrix ,elasticandfracturespropertiesofthefiber,geometricparametersofthefibers,arrangementofthefibersandthepropertyofthef… 相似文献