全文获取类型
收费全文 | 249篇 |
免费 | 9篇 |
国内免费 | 2篇 |
专业分类
化学 | 177篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 19篇 |
物理学 | 56篇 |
出版年
2023年 | 9篇 |
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 12篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 14篇 |
2012年 | 27篇 |
2011年 | 28篇 |
2010年 | 7篇 |
2009年 | 10篇 |
2008年 | 17篇 |
2007年 | 20篇 |
2006年 | 18篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1987年 | 3篇 |
1980年 | 1篇 |
排序方式: 共有260条查询结果,搜索用时 15 毫秒
91.
The biotin-(strept)avidin interaction remains a gold standard of model biological recognition events. The biotinylation of azamacrocycles permits the investigation of signal transduction between this recognition event and the metal center of an azamacrocycle complex, of wide potential interest in biosensing. There are no generally applicable procedures in the literature for such functionalizations. We report here a comprehensive investigation into the attachment of biotin to TACN, cyclen, and cyclam. Effective methods have been found for each ring. The efficacy of the functionalization is critically dependent on the nature of the azamacrocycle. 相似文献
92.
93.
94.
Lagi M Nostro PL Fratini E Ninham BW Baglioni P 《The journal of physical chemistry. B》2007,111(3):589-597
Water dispersions of dioctanoylphosphatidylcholine (diC8PC) exhibit upper consolute curves. How they are affected by some salts and other additives (D2O, urea) has already been explored and the phase separation has been interpreted within the framework of the Blankschtein-Thurston-Benedek (BTB) model. This deduces the chemical potential gain in micellar growth (Deltamu) and the intermicellar interaction coefficient (C) as fitting parameters from the coexistence curves. But, the specific mechanisms that drive such phenomena have remained obscure. To identify these mechanisms, we investigate the effects of a range of anions on the cloud points of diC8PC/H2O systems and extract the phenomenological parameters of the BTB model. We show how these parameters, for micellar growth, i.e., surface, intramolecular interactions, and for interaggregate interactions, i.e., bulk solute effects, are connected to anionic polarizabilities. Nonelectrostatic (NES) quantum mechanical fluctuation (Lifshitz or dispersion) forces missing from conventional theories are then shown to regulate lyotropic Hofmeister effects, both explicitly and implicitly. 相似文献
95.
Colafemmina G Fiorentino D Ceglie A Carretti E Fratini E Dei L Baglioni P Palazzo G 《The journal of physical chemistry. B》2007,111(25):7184-7193
The effect of propylene carbonate on SDS micelles was investigated by means of pulsed gradient spin-echo (PGSE) NMR, small-angle X-ray scattering (SAXS), conductivity and ion-selective electrode (ISE) measurements. The knowledge of the cosolvent partition between continuous phase and micelles (obtained by means of PGSE-NMR) allowed the identification of relevant dilution paths. Along these paths the system is composed of identical micelles that become more and more diluted. The extrapolation of measured self-diffusion coefficient to infinite dilution (where direct and hydrodynamic interactions are negligible) permits the determination of hydrodynamic size of the micelles. Moreover, the micelle ionization degree (measured by means of ISE) combined with PGSE-NMR and conductivity data furnishes an estimate of the aggregation number without any assumptions on micellar shape. On the other hand, troublesome hydrodynamic interactions are irrelevant to SAXS, and scattering data collected at fixed composition can be analyzed according to a reasonable model by exploiting the insight on the propylene carbonate partition gained through PGSE-NMR. By means of these approaches, we have found that propylene carbonate acts mainly as cosurfactant for the SDS micelles, decreasing their size and aggregation number by increasing the mean headgroup area of SDS. 相似文献
96.
We prove a Hadwiger transversal-type result, characterizing convex position on a family of non-crossing convex bodies in the plane. This theorem suggests
a definition for the order type of a family of convex bodies, generalizing the usual definition of order type for point sets. This order type turns out to
be an oriented matroid. We also give new upper bounds on the Erdős–Szekeres theorem in the context of convex bodies. 相似文献
97.
Antimo GioielloPaola Sabbatini Emiliano RosatelliAntonio Macchiarulo Roberto Pellicciari 《Tetrahedron》2011,67(10):1924-1929
A new divergent synthesis of DAF-12 ligands, namely Δ4- and Δ7-dafachronic acid, is described starting from the natural bile acid hyodeoxycholic acid. Homologation of the side chain followed by stereoselective reduction of the Δ24 olefinic linkage, 6α-dehydroxylation and C3-oxidation affords dafachronic acids in good yields and high diastereoselectivity making this approach easily accessible and scalable. 相似文献
98.
Brini E Marcon V van der Vegt NF 《Physical chemistry chemical physics : PCCP》2011,13(22):10468-10474
Systematically coarse grained models for complex fluids usually lack chemical and thermodynamic transferability. Efforts to improve transferability require the development of effective potentials with unequivocal physical significance. In this paper, we introduce conditional reversible work (CRW) potentials that describe nonbonded interactions in coarse grained models at the pair level. The method used to obtain these potentials is straightforward to implement, can be readily extended to compute hydration contributions in implicit-solvent potentials, and is easy to automize. As a first illustration of the method, we present CRW potentials for 3-site models of hexane and toluene. The temperature-transferability of the liquid phase density obtained with these potentials has been investigated, and a comparison has been made with effective potentials obtained by the iterative Boltzmann inversion method. 相似文献
99.
Angelova LV Terech P Natali I Dei L Carretti E Weiss RG 《Langmuir : the ACS journal of surfaces and colloids》2011,27(18):11671-11682
A gel-like, high-viscosity polymeric dispersion (HVPD) based on cross-linked borate, partially hydrolyzed poly(vinyl acetate) (xPVAc, where x is the percent hydrolysis) is described. Unlike hydro-HVPDs prepared from poly(vinyl alcohol) (PVA) and borate, the liquid portion of these materials can be composed of up to 75% of an organic cosolvent because of the influence of residual acetate groups on the polymer backbone. The effects of the degree of hydrolysis, molecular weight, polymer and cross-linker concentrations, and type and amount of organic cosolvent on the rheological and structural properties of the materials are investigated. The stability of the systems is explored through rheological and melting-range studies. (11)B NMR and small-angle neutron scattering (SANS) are used to probe the structure of the dispersions. The addition of an organic liquid to the xPVAc-borate HVPDs results in a drastic increase in the number of cross-linked borate species as well as the agglomeration of the polymer into bundles. These effects result in an increase in the relaxation time and thermal stability of the networks. The ability to make xPVAc-borate HVPDs with very large amounts of and rather different organic liquids, with very different rheological properties that can be controlled easily, opens new possibilities for applications of PVAc-based dispersions. 相似文献
100.
Diego Richard Emiliano L. Muñoz Leonardo A. Errico Mario Rentería 《Physica B: Condensed Matter》2012,407(16):3134-3136
In this work we present an ab initio study of Ta-doped Sc2O3 semiconductor. Calculations were performed at dilute Ta impurities located at both cationic sites of the host structure, using the Augmented Plane Wave plus Local Orbitals (APW+lo) method. The structural atomic relaxations and the electric-field gradients (EFG) were studied for different charge states of the cell in order to simulate different ionization states of the double-donor Ta impurity. From the results for the EFG tensor at Ta impurity sites and the comparison with experimental results obtained using the Time-Differential γ–γ Perturbed-Angular-Correlations technique we could determined the structural distortions induced by the Ta impurity and the electronic structure of the doped-semiconductor. 相似文献