全文获取类型
收费全文 | 234篇 |
免费 | 4篇 |
专业分类
化学 | 92篇 |
晶体学 | 1篇 |
力学 | 10篇 |
数学 | 13篇 |
物理学 | 122篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 1篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 12篇 |
2010年 | 7篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 5篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1939年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有238条查询结果,搜索用时 15 毫秒
121.
We prove the Lee-Huang-Yang formula for the ground state energy of the 3D Bose gas with repulsive interactions described by the exponential function, in a simultaneous limit of weak coupling and high density. In particular, we show that the Bogoliubov approximation is exact in an appropriate parameter regime, as far as the ground state energy is concerned. 相似文献
122.
123.
Bartoli G Bosco M Dalpozzo R Giuliani A Marcantoni E Mecozzi T Sambri L Torregiani E 《The Journal of organic chemistry》2002,67(25):9111-9114
2-Alkylidenecycloalkanones are powerful synthons used as the key intermediates in many important syntheses. Because of their potential, a general method of preparation from readily available starting materials, under very mild conditions, was considered to be worthwhile. Cerium(III) chloride heptahydrate in combination with sodium iodide in refluxing acetonitrile promotes a regio- and stereoselective beta-elimination reaction to (E)-2-alkylidenecycloalkanones in 2-(1-hydroxyalkyl)cycloalkanones. The synthetic value of the present procedure is demonstrated by the synthesis of monoterpene (S)-(-)-pulegone (8) in its optically active form. 相似文献
124.
125.
Arnaboldi C Brofferio C Cremonesi O Fiorini E Lo Bianco C Martensson L Nucciotti A Pavan M Pessina G Pirro S Previtali E Sisti M Giuliani A Margesin B Zen M 《Physical review letters》2003,91(16):161802
High statistics calorimetric measurements of the beta spectrum of 187Re are being performed with arrays of silver perrhenate crystals operated at low temperature. After a substantial modification of the experimental setup, a new measurement with ten silver perrhenate microbolometers has been running since July 2002. The crystals have masses around 300 microg and their average FWHM energy resolution is of 28.3 eV at the beta end point. The Kurie plot collected during 4485 h x mg effective running time has an end-point energy of 2466.1+/-0.8(stat)+/-1.5(syst) eV, while the half lifetime of the decay is found to be 43.2+/-0.2(stat)+/-0.1(syst) Gy. These values are the most precise obtained so far for 187Re. The best fit value for m(2)(nu(e)) is 147+/-237(stat)+/-90(syst) eV(2), which corresponds to an upper limit for the electron antineutrino mass m(nu(e))< or =21.7 eV at 90% C.L. 相似文献
126.
127.
C. Arnaboldi D. R. Artusa F. T. Avignone III M. Balata I. Bandac M. Barucci J. Beeman C. Brofferio C. Bucci S. Capelli L. Carbone S. Cebrian O. Cremonesi R. J. Creswick A. de Waard H. A. Farach A. Fascilla E. Fiorini G. Frossati A. Giuliani P. Gorla E. E. Haller I. G. Irastorza R. J. McDonald A. Morales E. B. Norman A. Nucciotti E. Olivieri V. Palmieri E. Pasca M. Pavan M. Pedretti G. Pessina S. Pirro E. Previtali C. Pobes M. Pyle L. Risegari C. Rosenfeld M. Sisti A. R. Smith L. Torres G. Ventura 《Physics of Atomic Nuclei》2004,67(6):1220-1226
The CUORICINO ββ-decay detector is an array of 62 TeO2 bolometers; 44 are 5×5×5-cm crystals made with natural tellurium (33.8% 130Te). There are 18, 3×3×6-cm crystals, 14 of which are made of natural tellurium, 2 are isotopically enriched to 75% in 130Te, and 2 are enriched to 82.3% in 128Te. The total mass of 130Te is ~ 11 kg. The background rate is 0.23 ± 0.04 counts/keV/kg/yr in the energy interval 2480 to 2600 keV. During the cooling process, some of the wires became disconnected and only 32 of the large and 16 of the smaller crystals could be read out. The data presented here come from 29 of the 5×5×5-cm crystals containing 6.2 kg of 130Te. The new limit on the half-life is $T_{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-0em} 2}}^{0\nu } \geqslant 5 \times 10^{23} yr$ , corresponding to an effective Majorana mass of the electron neutrino 〈m ν〉 between 0.42 and 2.05 eV, depending on the nuclear model used to analyze the data. 相似文献
128.
Relevant equivalent circuit parameters and values of material constants of a piezoelectric resonator can be determined from measurements of its electrical input impedance as a function of frequency. The complex electrical impedance curves and the associated critical frequencies are the basis of this characterization by the piezoelectric resonance method. In this paper, the previously introduced concept of normalized electrical impedance of the lossy resonator, extended to include piezoelectric losses, is applied to the analysis of the effects of different types of intrinsic losses on peak values, bandwidths and characteristic frequencies. The resulting impedance patterns depend solely on the electromechanical coupling coefficient and the loss tangents, providing a useful tool for the analysis of low-Q resonators. The normalized impedance is experimentally evaluated from the basic data provided by an HP 4194A impedance analyser by means of specifically developed ASP programs. 相似文献
129.
Rivard E Steiner J Fettinger JC Giuliani JR Augustine MP Power PP 《Chemical communications (Cambridge, England)》2007,(46):4919-4921
Two complementary synthetic routes to a pentagonal bipyramidal Sn7 cluster, Sn7Aryl2 (Aryl = terphenyl ligand), are reported. 相似文献
130.
Giuliani F 《Physical review letters》2005,95(10):101301
The common analysis of direct searches for spin-independent weakly interacting massive particles (WIMPs) assumes that a spin-independent WIMP couples with the same strength with both nucleons, i.e., that the spin-independent interaction is also fully isospin independent. Though in a fully isospin-dependent interaction scenario the spin-independent WIMP-nucleus cross section is strongly quenched, the leading experiments are still sensitive enough to set limits 1-2 orders of magnitude less stringent than those traditionally presented. In the isospin-dependent scenario the difference between the limits of CDMS-II and ZEPLIN-I is significantly reduced. Here, a model-independent framework is discussed and applied to obtain the current general model-independent limits. 相似文献