全文获取类型
收费全文 | 325篇 |
免费 | 10篇 |
国内免费 | 2篇 |
专业分类
化学 | 193篇 |
晶体学 | 5篇 |
力学 | 5篇 |
数学 | 77篇 |
物理学 | 57篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 13篇 |
2013年 | 30篇 |
2012年 | 20篇 |
2011年 | 29篇 |
2010年 | 23篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 10篇 |
2006年 | 16篇 |
2005年 | 15篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有337条查询结果,搜索用时 15 毫秒
91.
Geraldo Robson Mateus Cláudio Thomás Bornstein 《The Journal of the Operational Research Society》1991,42(2):145-149
The paper examines the capacitated warehouse location problem where fixed costs, generally relating to the installation of warehouses and variable costs, consisting mainly of transportation costs, are minimized. The minimization of each kind of cost drives the solution towards opposite directions with respect to the number of warehouses to be opened/closed. Therefore, dominance criteria between fixed and variable costs are examined. This leads to exact tests as well as greedy heuristics, the latter known in the literature as ADD/DROP techniques. 相似文献
92.
Adcox K Adler SS Ajitanand NN Akiba Y Alexander J Aphecetche L Arai Y Aronson SH Averbeck R Awes TC Barish KN Barnes PD Barrette J Bassalleck B Bathe S Baublis V Bazilevsky A Belikov S Bellaiche FG Belyaev ST Bennett MJ Berdnikov Y Botelho S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy J Butsyk S Carey TA Chand P Chang J Chang WC Chavez LL Chernichenko S Chi CY Chiba J Chiu M Choudhury RK Christ T Chujo T Chung MS Chung P Cianciolo V Cole BA D'Enterria DG 《Physical review letters》2001,86(16):3500-3505
We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality. 相似文献
93.
It is well known that continuous bilinear forms on C(K) × C(K) are 2-dominated. This paper shows that generalizations of this result are not to be expected. The main result asserts that for every
-space E(1 p ), every n 2, every r > 0 and every Banach space F , there exists an n-homogeneous polynomial P : E F such that P is not of type [r], hence P is neither r-dominated nor r-semi-integral (if n = 2 and p = , F is supposed to contain an isomorphic copy of some
, 1q < ).Received: 24 November 2003 相似文献
94.
Wang Y Botelho AV Martinez GV Brown MF 《Journal of the American Chemical Society》2002,124(26):7690-7701
Changes in lipid composition have recently been shown to exert appreciable influences on the activities of membrane-bound proteins and peptides. We tested the hypothesis that the conformational states of rhodopsin linked to visual signal transduction are related to biophysical properties of the membrane lipid bilayer. For bovine rhodopsin, the meta I-meta II conformational transition was studied in egg phosphatidylcholine (PC) recombinants versus the native rod outer segment (ROS) membranes by means of flash photolysis. Formation of metarhodopsin II was observed by the change in absorbance at 478 nm after a single actinic flash was delivered to the sample. The meta I/meta II ratio was investigated as a function of both temperature and pH. The data clearly demonstrated thermodynamic reversibility of the transition for both the egg PC recombinants and the native ROS membranes. A significant shift of the apparent pK(a) for the acid-base equilibrium to lower values was evident in the egg PC recombinant, with little meta II produced under physiological conditions. Calculations of the membrane surface pH using a Poisson-Boltzmann model suggested the free energies of the meta I and meta II states were significantly affected by electrostatic properties of the bilayer lipids. In the ROS membranes, phosphatidylserine (PS) is needed for full formation of meta II, in combination with phosphatidylethanolamine (PE) and polyunsaturated docosahexaenoic acid (DHA; 22:6omega3) chains. We propose that the PS surface potential leads to an accumulation of hydronium ions, H(3)O(+), in the electrical double layer, which drive the reaction together with the large negative spontaneous curvature (H(0)) conferred by PE plus DHA chains. The elastic stress/strain of the bilayer arises from an interplay of the approximately zero H(0) from PS and the negative H(0) due to the PE headgroups and polyunsaturated chains. The lipid influences are further explained in terms of matching of the bilayer spontaneous curvature to the curvature at the lipid/rhodopsin interface, as formulated by the Helfrich bending energy. These new findings guide current ideas as to how bilayer properties govern the conformational energetics of integral membrane proteins. Moreover, they yield knowledge of how membrane lipid-protein interactions involving acidic phospholipids such as PS and neutral polyunsaturated DHA chains are implicated in key biological functions such as vision. 相似文献
95.
Jorge E. P. Monteagudo Geraldo L. Rochocz Paulo L. C. Lage Krishnaswamy Rajagopal 《Fluid Phase Equilibria》2001,190(1-2):1-13
The computation of phase equilibrium for semicontinuous mixtures results in a set of algebraic-functional equations which are commonly solved using the pseudocomponent approach or reducing the order of the functional equations to a set of algebraic equations by means of a Petrov–Galerkin approach. Both approaches can be taken as particular cases of the method of weighed residuals. In order to perform stability analysis of phase equilibrium, the classical tangent plane criterion algorithms can be used as the first approach. There is a lack of functional formulation for the stability criterion in the literature. In some special cases, such as mixtures containing continuous families of heavy-components, a new formulation of the tangent plane criterion is required. In the present work, functional extensions of the Gibbs tangent plane criterion are described. The use of the proposed criteria was exemplified by calculating solid–liquid phase equilibrium of a crude oil containing asphaltenes on titration with a precipitating agent, n-pentane. 相似文献
96.
Oscar Blasco Geraldo Botelho Daniel Pellegrino Pilar Rueda 《Monatshefte für Mathematik》2011,23(1):131-147
In this paper we prove new results concerning summability properties of multilinear mappings between Banach spaces, such as
an extension of Littlewood’s 4/3 Theorem. The role of the Littlewood–Orlicz property in the theory is established, especially
in the question of determining when multilinear mappings are (1; 2, . . . , 2)-summing. 相似文献
97.
98.
99.
Synthesis,characterization and assessment of the cytotoxic activity of Cu(II), Fe(III) and Mn(III) complexes of camphoric acid‐derived salen ligands
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dina Murtinho Zênis N. da Rocha Ana Salomé Pires Roberto P. Jiménez Ana Margarida Abrantes Mafalda Laranjo Ana Catarina Mamede João Eduardo Casalta‐Lopes Maria Filomena Botelho Alberto A. C. C. Pais Sandra C. C. Nunes Hugh D. Burrows Telma Costa M. Elisa Silva Serra 《应用有机金属化学》2015,29(7):425-432
Novel Cu(II), Fe(III) and Mn(III) salen‐type metal complexes from (1R,3S)‐N,N′‐bis[salicylidene]‐1,3‐diamino‐1,2,2‐trimethylcyclopentane were synthesized and screened for their in vitro cytotoxic activity against three human cancer cell lines: melanoma, colorectal and breast. In vitro experiments carried out with the three metal complexes show that the copper complex exhibits the highest cytotoxic activity towards all cell lines studied, presenting IC50 values of 3.32–6.71 μM. A significant improvement in the anti‐proliferative effect, by 20‐fold, is observed with this complex when compared with conventional chemotherapy. The relationship between structure, redox characteristics and biological activity in human cancer cell lines was evaluated for the most efficient Cu(II) complex and associated with theoretical calculations. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
100.
J. Araujo J. Padrão J. P. Silva F. Dourado D. M. Correia G. Botelho J. L. Gomez Ribelles S. Lanceros-Méndez V. Sencadas 《Applied Physics A: Materials Science & Processing》2014,115(4):1291-1298
Elastin isolated from fresh bovine ligaments was dissolved in a mixture of 1,1,1,3,3,3-Hexafluoro-2-propanol and water were electrospun into fiber membranes under different processing conditions. Fiber mats of randomly and aligned fibers were obtained with fixed and rotating ground collectors and fibrils were composed by thin ribbons whose width depends on electrospinning conditions; fibrils with 721 nm up to 2.12 μm width were achieved. After cross-linking with glutaraldehyde, α-elastin can uptake as much as 1700 % of PBS solution and a slight increase on fiber thickness was observed. The glass transition temperature of electrospun fiber mats was found to occur at ~80 °C. Moreover, α-Elastin showed to be a perfect elastomeric material, and no mechanical hysteresis was found in cycle mechanical measurements. The elastic modulus obtained for random and aligned fibers mats in a PBS solution was 330±10 kPa and 732±165 kPa, respectively. Finally, the electrospinning and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Cell culture results showed good cell adhesion and proliferation in the cross-linked elastin fiber mats. 相似文献