全文获取类型
收费全文 | 237篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
化学 | 136篇 |
力学 | 29篇 |
数学 | 45篇 |
物理学 | 32篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 3篇 |
2013年 | 15篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 1篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有242条查询结果,搜索用时 15 毫秒
21.
Masciocchi N Ardizzoia GA Brenna S Castelli F Galli S Maspero A Sironi A 《Chemical communications (Cambridge, England)》2003,(16):2018-2019
Two new 3D homoleptic binary imidazolates, Cd(im)2 and Hg(im)2 (Him = imidazole), as well as [Hg(im)]NO3, containing 1D polycations of [Hg(im)]n(n+) formulation, have been prepared and characterized by ab-initio XRPD methods. 相似文献
22.
23.
We discuss local solvability of operators of the form
where theV
j
are left-invariant vector fields on the Heisenberg group such that [V
j
,V
j+n
]=U for 1≤j≤n andA=(a
jk
)=A
1+iA
2 is a complex symmetric matrix satisfying the “cone condition” |A
2|≤CA
1.
The authors acknowledge the support for this work by the European Commission through the European HCM-program “Fourier Analysis”
and the TMR network “Harmonic Analysis”. 相似文献
24.
Given a real polynomial in one variable such that , we consider the maximal operator in ,
We prove that is bounded on for 1$"> with bounds that only depend on the degree of .
0\,,\,i,j\in \mathbb{Z}}\frac{1... ...t f\big (x_{1}-2^{i}p(t),x_{2}-2^{j}p(t)\big )\big \vert\,dt . \end{displaymath}">
We prove that is bounded on for 1$"> with bounds that only depend on the degree of .
25.
Fulvio Ricci Giancarlo Travaglini 《Proceedings of the American Mathematical Society》2001,129(6):1739-1744
Let be a convex curve in the plane and let be the arc-length measure of Let us rotate by an angle and let be the corresponding measure. Let . Then This is optimal for an arbitrary . Depending on the curvature of , this estimate can be improved by introducing mixed-norm estimates of the form where and are conjugate exponents. 相似文献
26.
The paper tackles the problem of pricing, under interest-rate risk, a default-free sinking-fund bond which allows its issuer to recurrently retire part of the issue by (a) a lottery call at par, or (b) an open market repurchase. By directly modelling zero-coupon bonds as diffusions driven by a single-dimensional Brownian motion, a pricing formula is supplied for the sinking-fund bond based on a backward induction procedure which exploits, at each step, the martingale approach to the valuation of contingent-claims. With more than one sinking-fund date, however, the pricing formula is not in closed form, not even for simple parametrizations of the process for zerocoupon bonds, so that a numerical approach is needed. Since the computational complexity increases exponentially with the number of sinking-fund dates, arbitrage-based lower and upper bounds are provided for the sinking-fund bond price. The computation of these bounds is almost effortless when zero-coupon bonds are as described by Cox, Ingersoll and Ross. Numerical comparisons between the price of the sinking-fund bond obtained via Monte Carlo simulation and these lower and upper bounds are illustrated for different choices of parameters. 相似文献
27.
28.
Antonella De Palma Antonella Roveri Mattia Zaccarin Louise Benazzi Simone Daminelli Giorgia Pantano Mauro Buttarello Fulvio Ursini Massimo Gion Pier Luigi Mauri 《Journal of chromatography. A》2010,1217(33):5328-5336
Since red blood cells (RBCs) lack nuclei and organelles, cell membrane is their main load-bearing component and, according to a dynamic interaction with the cytoskeleton compartment, plays a pivotal role in their functioning. Even if erythrocyte membranes are available in large quantities, the low abundance and the hydrophobic nature of cell membrane proteins complicate their purification and detection by conventional 2D gel-based proteomic approaches. So, in order to increase the efficiency of RBC membrane proteome identification, here we took advantage of a simple and reproducible membrane sub-fractionation method coupled to Multidimensional Protein Identification Technology (MudPIT). In addition, the adoption of a stringent RBC filtration strategy from the whole blood, permitted to remove exhaustively contaminants, such as platelets and white blood cells, and to identify a total of 275 proteins in the three RBC membrane fractions collected and analysed. Finally, by means of software for the elaboration of the great quantity of data obtained and programs for statistical analysis and protein classification, it was possible to determine the validity of the entire system workflow and to assign the proper sub-cellular localization and function for the greatest number of the identified proteins. 相似文献
29.
The dominant noises which limit the present sensitivity of the gravitational wave detectors are the thermal noise of the suspended
mirrors and the shot noise. For the third generation of gravitational wave detectors as the Einstein Telescope (ET), the reduction
of the shot noise implies to increase the power stored in the detector at 1 MW level and, at the same time, to compensate
the huge optic distortion due to induced thermal lensing. At low temperature it is possible to reduce both these effects.
However, lowering the temperature of the test masses without injecting vibration noise from the cooling system is a technological
challenge. We review here the thermal noise impact on the ultimate ET sensitivity limit and we discuss possible cryogenic
configurations to cool the mirror. 相似文献
30.
Martin Blom Fulvio Castellacci Arne Fevolden 《Computational & Mathematical Organization Theory》2014,20(4):430-461
The paper presents an agent-based simulation model of the European defence industry. The model resembles some of the key characteristics of the defence sector, and studies how firms in this market will respond to the challenges and opportunities provided by a higher degree of openness and liberalization in the future. The simulation analysis points out that European defence firms will progressively become more efficient, less dependent on public procurement and innovation policy support, and more prone to knowledge sharing and inter-firm collaborations. This firm-level dynamics will in the long-run lead to an increase in the industry’s export propensity and a less concentrated export market. 相似文献