全文获取类型
收费全文 | 3126篇 |
免费 | 146篇 |
国内免费 | 24篇 |
专业分类
化学 | 2090篇 |
晶体学 | 11篇 |
力学 | 100篇 |
数学 | 615篇 |
物理学 | 480篇 |
出版年
2023年 | 16篇 |
2022年 | 35篇 |
2021年 | 41篇 |
2020年 | 52篇 |
2019年 | 70篇 |
2018年 | 52篇 |
2017年 | 34篇 |
2016年 | 81篇 |
2015年 | 100篇 |
2014年 | 89篇 |
2013年 | 201篇 |
2012年 | 208篇 |
2011年 | 224篇 |
2010年 | 146篇 |
2009年 | 120篇 |
2008年 | 204篇 |
2007年 | 189篇 |
2006年 | 162篇 |
2005年 | 142篇 |
2004年 | 152篇 |
2003年 | 118篇 |
2002年 | 112篇 |
2001年 | 46篇 |
2000年 | 46篇 |
1999年 | 30篇 |
1998年 | 38篇 |
1997年 | 27篇 |
1996年 | 45篇 |
1995年 | 29篇 |
1994年 | 29篇 |
1993年 | 22篇 |
1992年 | 29篇 |
1991年 | 18篇 |
1989年 | 27篇 |
1988年 | 18篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 28篇 |
1984年 | 30篇 |
1983年 | 18篇 |
1982年 | 21篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 17篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1976年 | 15篇 |
1975年 | 15篇 |
1974年 | 17篇 |
1973年 | 20篇 |
排序方式: 共有3296条查询结果,搜索用时 15 毫秒
11.
Joe Warren Scott Schaefer Anil N. Hirani Mathieu Desbrun 《Advances in Computational Mathematics》2007,27(3):319-338
In this paper we provide an extension of barycentric coordinates from simplices to arbitrary convex sets. Barycentric coordinates
over convex 2D polygons have found numerous applications in various fields as they allow smooth interpolation of data located
on vertices. However, no explicit formulation valid for arbitrary convex polytopes has been proposed to extend this interpolation
in higher dimensions. Moreover, there has been no attempt to extend these functions into the continuous domain, where barycentric
coordinates are related to Green’s functions and construct functions that satisfy a boundary value problem. First, we review
the properties and construction of barycentric coordinates in the discrete domain for convex polytopes. Next, we show how
these concepts extend into the continuous domain to yield barycentric coordinates for continuous functions. We then provide
a proof that our functions satisfy all the desirable properties of barycentric coordinates in arbitrary dimensions. Finally,
we provide an example of constructing such barycentric functions over regions bounded by parametric curves and show how they
can be used to perform freeform deformations.
相似文献
12.
13.
14.
Fatima Hassine Said Gmouh Mathieu Pucheault Michel Vaultier 《Monatshefte für Chemie / Chemical Monthly》2007,57(12):1167-1174
In this work was presented an application of the use of task specific onium salts (TSOSs) as soluble supports in Grieco’s multicomponent synthesis of tetrahydroquinolines. These soluble supports are of wide applicability and combine advantages
of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products
were cleaved from the supports and obtained in pure form and good yields. 相似文献
15.
16.
Let X be a 1-connected CW-complex of finite type and ε?(X) be the group of homotopy classes of self-equivalences of X which induce the identity on homotopy groups. In this paper, we prove that every finitely generated 2-solvable rational nilpotent group is realizable as ε?(X) where X is the rationalization of a 1-connected CW-complex of finite type. 相似文献
17.
In this paper one specifies the ergodic behavior of the 2D-stochastic Navier–Stokes equation by giving a Large Deviation Principle for the occupation measure for large time. It describes the exact rate of exponential convergence. The considered random force is non-degenerate and compatible with the strong Feller property. 相似文献
18.
19.
Sequence distribution of atactic poly(phenylvinylketone) (PPVK) has been determined by [13C]-[1H]NMR spectroscopy. Quantitative analysis of the carbonyl pattern allows resolution into pentads with intensities fitting a first order Markov process. The carbonyl pattern of highly isotactic PPVK, initiated by diethylzinc, deviates strongly from Bernoullian statistics, as in the case of highly isotactic polymethylvinylketone (PMVK). For n-butyl-lithium initiated poly(isopropenylphenylvinylketone) (PIPK), the carbonyl pattern practically agrees with a Bernoullian distribution. Atactic PMVK, analyzed from the methylene and the carbonyl pattern in [13C] or [1H]NMR, shows that the polymerization process is purely Bernoullian and quite different from that for poly(isopropenylmethylketone). Except for poly(methylallylalcohol) for which the tacticity can be determined, the resolution is too poor to allow a quantitative sequence distribution of poly(allylalcohols) or poly(allyltrifluoroacetates). [1H] and [19F]NMR spectroscopies of these compounds do not give better results. 相似文献
20.
Two bases of states are presented for modules of the graded parafermionic conformal field theory associated to the coset
. The first one is formulated in terms of the two fundamental (i.e., lowest-dimensional) parafermionic modes. In that basis, one can identify the completely reducible representations, i.e., those whose modules contain an infinite number of singular vectors; the explicit form of these vectors is also given. The second basis is a quasiparticle basis, determined in terms of a modified version of the
exclusion principle. A novel feature of this model is that none of its bases are fully ordered and this reflects a hidden structural
exclusion principle. 相似文献