全文获取类型
收费全文 | 157篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
化学 | 63篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 17篇 |
物理学 | 82篇 |
出版年
2024年 | 1篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 15篇 |
2007年 | 12篇 |
2006年 | 12篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2000年 | 1篇 |
1998年 | 5篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1971年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有166条查询结果,搜索用时 46 毫秒
121.
Kushal C. Lekhok Debajyoti Bhuyan Dipak Prajapati Romesh C. Boruah 《Molecular diversity》2010,14(4):841-846
An environmentally friendly and highly efficient procedure for the preparation of quinolines and fused polycyclic quinolines
has been developed by a simple Friedlander annulation reaction of 2-aminoaryl ketone with carbonyl compounds in presence of
zinc triflate under microwave irradiation and solvent-free conditions. The reaction also proceeds effectively when In(OTf)3 was used in lieu of Zn(OTf)2 as the catalyst. The catalyst can be recovered after the reaction and reused efficiently in subsequent runs. 相似文献
122.
We study bicomponents in networks, sets of nodes such that each pair in the set is connected by at least two independent paths, so that the failure of no single node in the network can cause them to become disconnected. We show that standard network models predict there to be essentially no small bicomponents in most networks, but there may be a giant bicomponent, whose presence coincides with the presence of the ordinary giant component, and we find that real networks seem by and large to follow this pattern, although there are some interesting exceptions. We also study the size of the giant bicomponent as nodes in the network fail and find in some cases that our networks are quite robust to failure, with large bicomponents persisting until almost all vertices have been removed. 相似文献
123.
Rahul Basu Debajyoti Choudhury H. S. Mani 《The European Physical Journal C - Particles and Fields》2009,61(3):461-470
The dynamics of fermionic unparticles is developed from first principles. It is shown that any unparticle, whether fermionic
or bosonic, can be recast in terms of a canonically quantized field, but with non-local interaction terms. We further develop
a possible gauge theory for fermionic unparticles. Computing the consequent contribution of unfermions to the β function of the theory, it is shown that this can be viewed as the sum of two contributions, one fermion-like and the other
scalar-like. However, if full conformal invariance is imposed, the latter vanishes identically. We discuss the consequences
thereof as well as some general phenomenological issues. 相似文献
124.
Sandhya Choubey Debajyoti Dutta Dipyaman Pramanik 《The European Physical Journal C - Particles and Fields》2018,78(4):339
The CP phases associated with the sterile neutrino cannot be measured in the dedicated short-baseline experiments being built to test the sterile neutrino hypothesis. On the other hand, these phases can be measured in long-baseline experiments, even though the main goal of these experiments is not to test or measure sterile neutrino parameters. In particular, the sterile neutrino phase \(\delta _{24}\) affects the charged-current electron appearance data in long-baseline experiment. In this paper we show how well the sterile neutrino phase \(\delta _{24}\) can be measured by the next-generation long-baseline experiments DUNE, T2HK (and T2HKK). We also show the expected precision with which this sterile phase can be measured by combining the DUNE data with data from T2HK or T2HKK. The T2HK experiment is seen to be able to measure the sterile phase \(\delta _{24}\) to a reasonable precision. We also present the sensitivity of these experiments to the sterile mixing angles, both by themselves, as well as when DUNE is combined with T2HK or T2HKK. 相似文献
125.
We show that matter effects change the numu-->nutau oscillation probability by as much as 70% for certain ranges of energies and path lengths. Consequently, the numu-->nutau survival probability also undergoes large changes. A proper understanding of numu survival rates must consider matter effects in Pmutau as well as Pmue. We comment on (a) how these matter effects may be observed and the sign of Delta31 determined in atmospheric neutrino measurements and at neutrino factories, and (b) how they lead to heightened sensitivity for small theta13. 相似文献
126.
Sudhansu S. Biswal Debajyoti Choudhury Rohini M. Godbole Ritesh K. Singh 《Pramana》2007,69(5):777-782
We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to a
pair of gauge bosons, including the possibility of CP violation. We construct several observables that probe the various possible
anomalous couplings. For an intermediate mass Higgs, a collider operating at a center of mass energy of 500 GeV and with an
integrated luminosity of 500 fb−1 is shown to be able to constrain the ZZH vertex at the few per cent level, with even higher sensitivity for some of the couplings. However, lack of sufficient number
of observables as well as contamination from the ZZH vertex limits the precision to which anomalous part of the WWH coupling can be probed.
相似文献
127.
Swadesh Kumar Ghoshal Sankar Sengupta 《Journal of Quantitative Spectroscopy & Radiative Transfer》1982,27(1):107-108
The Hulburt-Hirschfelder potential function is capable of reproducing a potential hump in the excited 1Σu+ state of the argon dimer, as expected from experimental findings of Tanaka and Yoshino. 相似文献
128.
Summary An attempt is made to study the thermoelectric power of the carriers in quantum well of A
3
II
B
2
V
semiconductors, taking Cd3As2 quantum well as an example. It is found, on the basis of newly derived 2DE−k
s
dispersion relation by including various types of anisotropies in the energy spectrum that the thermoelectric power decreases
with increasing electron concentration and decreasing film thickness respectively. In addition, the corresponding well-known
results for bulk specimens of isotropic parabolic energy bands are also obtained from the expressions derived. 相似文献
129.
Ashoke BhattacharjeeSeema Datta Partha ChattopadhyayNanda Ghoshal Asish P KunduArani Pal Ranjan MukhopadhyaySandip Chowdhury Anup Bhattacharjya Amarendra Patra 《Tetrahedron》2003,59(25):4623-4639
3-O-Allylcarbohydrate nitrone cycloaddition (3-OACNC) furnished pyran and oxepane derivatives from 3-O-allyl hexose N-benzyl nitrones and 3-O-allyl furanoside-5-aldehyde N-benzyl/methyl nitrones. The regioselectivity of 3-OACNC was found to depend on the following factors (a) the structural nature of the nitrone (b) substitution and stereochemistry at 3-C of the carbohydrate backbone (c) substitution at the terminus of the O-allyl moiety. Oxepanes or pyrans obtained from a particular set of a hexose nitrone and the corresponding furanoside nitrone were converted to enantiomeric cyclic ethers through degradation. A mixture of an oxepane and a pyran was formed in the intramolecular oxime olefin cycloaddition (IOOC) of a 3-O-allylcarbohydrate derived oxime. 相似文献
130.
Ghoshal D Maji TK Mostafa G Sain S Lu TH Ribas J Zangrando E Chaudhuri NR 《Dalton transactions (Cambridge, England : 2003)》2004,(11):1687-1695
Four succinato-bridged complexes of copper(II) have been synthesized. Complex 1, [Cu(2)(mu-OH(2))(2)L(bpy)(2)(NO(3))(2)](n) and 2, [Cu(2)(mu-OH(2))(2)L(phen)(2)(NO(3))(2)](n)(bpy = 2,2[prime or minute]-bipyridine; phen = 1,10-phenanthroline and LH(2)= succinic acid) exhibit 1D coordination polymer structures where both the nitrate ions are directly linked to the copper(ii) producing synthons in a 2D sheet. A novel 2D grid-like network, ([Cu(4)L(2)(bpy)(4)(H(2)O)(2)](ClO(4))(4)(H(2)O))n3, is obtained upon changing the nitrate by perchlorate anion in complex 1, where the channels are occupied by the anions. On changing the nitrate by tetrafluoroborate anion in complex 2, a novel octanuclear complex, [Cu(8)L(4)(phen)(12)](BF(4))(8).8H(2)O 4, is isolated. The coligand bpy and phen in these complexes show face-to-face (in 1,2,3,4) or edge-to-face (in 4 )pi-pi interactions forming the multidimensional supramolecular architectures. Interestingly, the appearance of edge-to-face pi-pi interactions in complex facilitates the formation of discrete octanuclear entities. Variable-temperature (300-2 K) magnetic measurements of complexes have been done. Complexes 1 and 2 show very weak antiferromagnetic (OOC-CH(2)-CH(2)-COO) and ferromagnetic coupling (mu-H(2)O). Complex 3 also shows antiferromagnetic (syn-syn mu-OCO), and ferromagnetic coupling (mu-O of the -COO group). Complex 4 with two types (syn-syn and syn-anti) of binding modes of the carboxylate group shows strong antiferromagnetic interaction. 相似文献