全文获取类型
收费全文 | 264篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
化学 | 196篇 |
晶体学 | 5篇 |
力学 | 5篇 |
数学 | 12篇 |
物理学 | 59篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 15篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 17篇 |
2013年 | 15篇 |
2012年 | 22篇 |
2011年 | 26篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 13篇 |
2007年 | 17篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有277条查询结果,搜索用时 15 毫秒
171.
Dr. Bishnu Prasad Bastakoti Dr. Yunqi Li Dr. Sudhina Guragain Dr. Malay Pramanik Prof. Saad M. Alshehri Dr. Tansir Ahamad Dr. Zongwen Liu Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(22):7463-7467
Mesoporous iron phosphate (FePO4) was synthesized through assembly of polymeric micelles made of asymmetric triblock co‐polymer (polystyrene‐b‐poly‐2‐vinylpyridine‐b‐ethylene oxide; PS‐PVP‐PEO). The phosphoric acid solution stimulates the formation of micelles with core–shell‐corona architecture. The negatively charged PO43? ions dissolved in the solution strongly interact with the positively charged PVP+ units through an electrostatic attraction. Also, the presence of PO43? ions realizes a bridge between the micelle surface and the metal ions. The removal of polymeric template forms the robust framework of iron phosphate with 30 nm pore diameter and 15 nm wall thickness. Our method is applicable to other mesoporous metal phosphates by changing metal sources. The obtained materials were fully characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption–desorption, Raman spectroscope, and other techniques. 相似文献
172.
173.
In the present paper, dynamics of generalized charged particles are studied in the presence of external electromagnetic interactions. This particular extension of the free relativistic particle model lives in Non-Commutative κ-Minkowski space–time, compatible with Doubly Special Relativity, that is motivated to describe Quantum Gravity effects. Furthermore we have also considered the electromagnetic field to be dynamical and have derived the modified forms of Lienard–Wiechert like potentials for these extended charged particle models. In all the above cases we exploit the new and extended form of κ-Minkowski algebra where electromagnetic effects are incorporated in the lowest order, in the Dirac framework of Hamiltonian constraint analysis. 相似文献
174.
Nayan Roy Harun A. R. Pramanik Pradip C. Paul Sanjoy T. Singh 《Journal of fluorescence》2014,24(4):1099-1106
A Schiff-base fluorescent probe – N, N/-bis(salicylidene) trans 1, 2 – diaminocyclohexane (H 2 L) was synthesized and evaluated as a chemoselective Zn2+ sensor. Upon treatment with Zn2+, the complexation of H 2 L with Zn2+ resulted in a bathochromic shift with a pronounced enhancement in the fluorescence intensity in ethanol solution. Moreover, other common alkali, alkaline earth and transition metal ions failed to induce response or minimal spectral changes. Notably, this chemosensor could distinguish clearly Zn2+ from Cd2+. The stoichiometric ratio and association constant were evaluated using Benesi – Hildebrand relation giving 1:1 stoichiometry. This further corroborated 1:1 complex formation based on Job’s plot analyses. 相似文献
175.
Recently, it has been shown that heme binds to Aβ peptides which may play a major role in Alzheimer's disease (AD). This study illustrates that Aβ peptides can bind both Cu and heme cofactors at the same time. Both cofactors have unique spectroscopic and electrochemical features which are unaffected in the presence of the other, implying that they are electronically, chemically, and electrochemically uncoupled. These data clearly indicate that Cu cannot bind to three histidine residues simultaneously in Cu-Aβ complexes as previously proposed, since one of the histidines is involved in binding heme. The heme-Aβ and the heme-Cu-Aβ peptide complexes function as peroxidases. Interestingly, the Cu-Aβ complex also exhibits peroxidase activity, which may have significant implications in AD. Both Cu(+)-Aβ and heme (Fe(2+))-Aβ complexes reduce O(2) to H(2)O(2) quantitatively. Only one of the two electrons that are required for the reduction of O(2) to H(2)O(2) is derived from the reduced metal site, while the Tyr(10) residue of the native Aβ peptide donates the second electron. This Tyr(10) residue, the source of electron for the generation of partially reduced oxygen species (PROS, e.g., H(2)O(2)) is absent in rodents, which do not get affected by AD. When both heme and Cu are bound to the Aβ peptides, which is likely to happen physiologically, the amount of toxic PROS generated is maximum, implying that heme-Cu-Aβ complexes could potentially be most toxic for AD. 相似文献
176.
Arjunolic acid, a functionally rich chiral triterpenoid with a rigid pentacyclic backbone, has the potential to be used as a structural framework for the design of molecular receptors and supramolecular architectures. The design and synthesis of the first arjunolic acid-derived 18-crown-6 and its binding studies with metal and tert-butylammonium ions are reported. 相似文献
177.
Amitava Pramanik Rashmi P. Kalagi Vishal J. Barge Shridhar R. Gadre 《Theoretical chemistry accounts》2005,114(1-3):129-136
Water adsorption is studied on medium-sized clusters of sodium chloride representing (100) and (110) surfaces at the ab initio
level. Topographical features of molecular electrostatic potential (MESP) have been employed for predicting the potent sites
for binding of one to four water molecules on these surfaces. Such guess geometries are initially optimized using an electrostatics-based
model, electrostatic potential for intermolecular complexation (EPIC) and further at the Hartree–Fock and B3LYP/6-31G(d, p)
levels. The corresponding interaction energies are examined for assessing co-operative binding effects. The geometry and interaction
energy of four water molecules adsorbed on NaCl(100) clearly brings out the co-operative binding among the water molecules.
Further, water binding to (110) surface is stronger than that with (100) surface. This is also in confirmation with the electrostatic
properties of (110) surface. Many-body decomposition analysis brings out the stronger interaction between NaCl clusters with
water molecules vis-a-vis water–water interaction. 相似文献
178.
A short, simple and inexpensive synthesis of several diversely substituted benzo[b]thiophenes and one naphthothiophene is described. The method involves introduction of methylsulfanyl group ortho- to the amide function of readily available N,N-diethylamides of aryl carboxylic acid by directed metalation. Thioindoxyls, obtained in high yields through side-chain deprotonation and cyclisation in one pot, are reduced to benzo[b]thiophene or napthothiophene. 相似文献
179.
Transition Metal Chemistry - 相似文献
180.
We obtain L2 decay estimates in λ for oscillatory integral operators Tλ whose phase functions are homogeneous polynomials of degree m and satisfy various genericity assumptions. The decay rates obtained are optimal in the case of (2+2)-dimensions for any m, while in higher dimensions the result is sharp for m sufficiently large. The proof for large m follows from essentially algebraic considerations. For cubics in (2+2)-dimensions, the proof involves decomposing the operator near the conic zero variety of the determinant of the Hessian of the phase function, using an elaboration of the general approach of Phong and Stein [D.H. Phong, E.M. Stein, Models of degenerate Fourier integral operators and Radon transforms, Ann. of Math. (2) 140 (1994) 703-722]. 相似文献