全文获取类型
收费全文 | 268篇 |
免费 | 2篇 |
国内免费 | 4篇 |
专业分类
化学 | 158篇 |
力学 | 3篇 |
数学 | 49篇 |
物理学 | 64篇 |
出版年
2020年 | 3篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2013年 | 8篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1993年 | 6篇 |
1991年 | 6篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 14篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1968年 | 9篇 |
1967年 | 7篇 |
1966年 | 5篇 |
1962年 | 4篇 |
1960年 | 7篇 |
1958年 | 3篇 |
1957年 | 9篇 |
1955年 | 2篇 |
1949年 | 2篇 |
1936年 | 2篇 |
1935年 | 2篇 |
1933年 | 2篇 |
1931年 | 2篇 |
1930年 | 2篇 |
1929年 | 2篇 |
排序方式: 共有274条查询结果,搜索用时 46 毫秒
91.
Calculation of electron-cyclotron-current drive (ECCD) with the comprehensive CQL3D Fokker-Planck code for a TCV tokamak shot gives 550 kA of driven toroidal current, in marked disagreement with the 100-kA experimental value. Published ECCD efficiencies calculated with CQL3D in the much larger, higher-confinement DIII-D tokamak are in excellent agreement with experiment. The disagreement is resolved by including in the calculations electrostatic-type radial transport at levels given by global energy confinement in tokamaks. The radial transport of energy and toroidal current are in agreement. 相似文献
92.
In this paper, we will consider hypersingular integrals as they arise by transforming elliptic boundary value problems into boundary integral equations. First, local representations of these integrals will be derived. These representations contain so-called finite-part integrals. In the second step, these integrals are reformulated as improper integrals. We will show that these integrals can be treated by cubature methods for weakly singular integrals as they exist in the literature.
93.
94.
95.
We study the regular part of a densely defined sectorial form, first in the abstract setting and then under mild conditions
for a differential sectorial form. The regular part of the latter turns out to be again a differential sectorial form. Moreover,
we characterize when taking the real part of a differential sectorial form commutes with taking the regular part. An example
shows that these two operations do not commute in general. 相似文献
96.
This paper gives one-term componentwise asymptotics for theM and spectral matrices of a self-adjoint realisation of aneven-order ordinary differential expression. The underlyinginterval is assumed to have at least one regular endpoint, andthe boundary conditions are supposed to be separated. Furthermore,the weight function and the reciprocal of the highest-ordercoefficient are supposed to be of regular variation at the regularendpoint, in the sense of Bingham, Goldie and Teugels. 1991Mathematics Subject Classification: 34B24, 34E05. 相似文献
97.
E. W. H. Hayek P. Krenmayr H. Lohninger U. Jordis F. Sauter W. Moche 《Fresenius' Journal of Analytical Chemistry》1991,340(3):153-156
Summary 100 mg amounts of glue on two copper-age arrowheads have been investigated by means of gas-chromatography/mass spectrometry and chemometrics. The samples have been identified as birch bark derivatives, but the distribution patterns of triterpenoids and steroids show significant differences to similar samples from younger archaeological periods that can be explained by the use of a different species of birch and a different method of preparation. 相似文献
98.
Derivatives of 5H-thiazolo[3.2?a]thieno[2.3?d]pyrimidine(A), 5H-[1]benzothieno[2.3?d]thiazolo[3.2?a]pyrimidine (B), 4H-thiazolo[3.2?a]thieno[3.2?e]pyrimidine (C) and 5H-[1]benzo-thieno[3.2?e]thiazolo[3.2?a]pyrimidine (D) were synthesized by various methods. Similar reactions are leading to derivatives of thieno[2′.3′∶4.5]pyrimido[2.1?b][1.3]thiazine (E) and [1]benzothieno[2′.3′∶4.5]pyrimido[2.1?b][1.3]thiazine (F).C, D, E, andF are new heterocyclic ring systems. Detailed papers will appear soon. 相似文献
99.
Prof. Dr. F. Sauter G. Büyük U. Jordis 《Monatshefte für Chemie / Chemical Monthly》1974,105(4):869-876
Derivatives of 1H-[1]Benzothieno[3,2?c]pyrazole were synthesized by a new method: 1.3-dipolar cycloaddition of substituted benzo[b]thiophene-1.1-dioxides with C-methyl-N-phenyl and C,N-diaryl-nitrilimines, resp., gave the corresponding title compounds. The structure was proved by conversion to known compounds. 相似文献
100.
In this paper, we will propose a boundary element method for solving classical boundary integral equations on complicated
surfaces which, possibly, contain a large number of geometric details or even uncertainties in the given data. The (small)
size of such details is characterised by a small parameter and the regularity of the solution is expected to be low in such zones on the surface (which we call the wire-basket zones).
We will propose the construction of an initial discretisation for such type of problems. Afterwards standard strategies for boundary element discretisations can be applied
such as the h, p, and the adaptive hp-version in a straightforward way.
For the classical boundary integral equations, we will prove the optimal approximation results of our so-called wire-basket boundary element method and discuss the stability aspects. Then, we construct the panel-clustering and -matrix approximations to the corresponding Galerkin BEM stiffness matrix. The method is shown to have an almost linear complexity
with respect to the number of degrees of freedom located on the wire basket. 相似文献