全文获取类型
收费全文 | 344篇 |
免费 | 3篇 |
专业分类
化学 | 88篇 |
力学 | 2篇 |
数学 | 5篇 |
物理学 | 252篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 7篇 |
2008年 | 28篇 |
2007年 | 35篇 |
2006年 | 25篇 |
2005年 | 30篇 |
2004年 | 39篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 11篇 |
2000年 | 11篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 5篇 |
1975年 | 1篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1936年 | 1篇 |
1891年 | 2篇 |
排序方式: 共有347条查询结果,搜索用时 15 毫秒
341.
Aubert B Barate R Boutigny D Couderc F Karyotakis Y Lees JP Poireau V Tisserand V Zghiche A Grauges E Palano A Pappagallo M Pompili A Chen JC Qi ND Rong G Wang P Zhu YS Eigen G Ofte I Stugu B Abrams GS Battaglia M Breon AB Brown DN Button-Shafer J Cahn RN Charles E Day CT Gill MS Gritsan AV Groysman Y Jacobsen RG Kadel RW Kadyk J Kerth LT Kolomensky YG Kukartsev G Lynch G Mir LM Oddone PJ Orimoto TJ Pripstein M Roe NA Ronan MT Wenzel WA Barrett M Ford KE Harrison TJ Hart AJ Hawkes CM Morgan SE 《Physical review letters》2005,95(14):142001
We study initial-state radiation events, e+ e- --> gammaISR pi+ pi- J/psi, with data collected with the BABAR detector. We observe an accumulation of events near 4.26 GeV/c2 in the invariant-mass spectrum of pi+ pi- J/psi. Fits to the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/c2 is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to 90 MeV/c2, depending on the fit hypothesis. 相似文献
342.
Aubert B Barate R Boutigny D Couderc F Karyotakis Y Lees JP Poireau V Tisserand V Zghiche A Grauges-Pous E Palano A Pompili A Chen JC Qi ND Rong G Wang P Zhu YS Eigen G Ofte I Stugu B Abrams GS Borgland AW Breon AB Brown DN Button-Shafer J Cahn RN Charles E Day CT Gill MS Gritsan AV Groysman Y Jacobsen RG Kadel RW Kadyk J Kerth LT Kolomensky YG Kukartsev G Lynch G Mir LM Oddone PJ Orimoto TJ Pripstein M Roe NA Ronan MT Wenzel WA Barrett M Ford KE Harrison TJ Hart AJ Hawkes CM Morgan SE 《Physical review letters》2005,94(17):171801
We search for the factorization-suppressed decays B-->chi(c0)K(*) and B-->chi(c2)K(*), with chi(c0) and chi(c2) decaying into J/psi gamma, using a sample of 124 x 10(6) BB events collected with the BABAR detector at the PEP-II storage ring of the Stanford Linear Accelerator Center. We find no significant signal and set upper bounds for the branching fractions. 相似文献
343.
R.M. Lees Reba-Jean Murphy Adriana Predoi-Cross D.R.T. Appadoo R.R.J. Goulding 《Journal of Molecular Spectroscopy》2009,256(1):91-98
The high-resolution Fourier transform spectrum of the ν8 CO-stretching band of CH318OH between 900 and 1100 cm−1 has been recorded at the Canadian Light Source (CLS) synchrotron facility in Saskatoon, and the majority of the torsion-rotation structure has been analyzed. For the νt = 0 torsional ground state, subbands have been identified for K values from 0 to 11 for A and E torsional symmetries up to J values typically well over 30. For νt = 1, A and E subbands have been assigned up to K = 7, and several νt = 2 subbands have also been identified. Upper-state term values determined from the assigned transitions using the Ritz program have been fitted to J(J + 1) power-series expansions to obtain substate origins and sets of state-specific parameters giving a compact representation of the substate J-dependence. The νt = 0 subband origins have been fitted to effective molecular constants for the excited CO-stretching state and a torsional barrier of 377.49(32) cm−1 is found, representing a 0.89% increase over the ground-state value. The vibrational energy for the CO-stretch state was found to be 1007.49(7) cm−1. A number of subband-wide and J-localized perturbations have been seen in the spectrum, arising both from anharmonic and Coriolis interactions, and several of the interacting states have been identified. 相似文献
344.
Sardar K Hong J Catalan G Biswas PK Lees MR Walton RI Scott JF Redfern SA 《J Phys Condens Matter》2012,24(4):045905
The crystal structure and physical properties of multiferroic polycrystalline Ca(2+)-doped BiFeO(3) samples have been investigated. The present experimental investigation suggests that Bi(1-x)Ca(x)FeO(3-x/2) (x ≤ 0.1) can be considered as a solid solution between BiFeO(3) and CaFeO(2.5). The oxidation state of Fe in these materials is + 3 and charge balance occurs through the creation of oxygen vacancies. For each composition, two structural phase transitions are revealed as anomalies in the variable-temperature in situ x-ray diffraction data which is consistent with the well-established high-temperature structural transformation in pure BiFeO(3). All compositions studied show antiferromagnetic behaviour along with a ferromagnetic component that increases with Ca(2+) doping. The resistivities of the Bi(1-x)Ca(x)FeO(3-x/2) samples at room temperature are of the order of 10(9) Ω cm and decrease with increasing Ca(2+) content. Arrhenius plots of the resistivity show two distinct linear regions with activation energies in the range of 0.4-0.7 and 0.03-0.16 eV. A correlation has been established between the critical temperatures associated with the structural phase transitions and the multiferroic properties. A composition of x = 0.085 is predicted to show maximum magneto-electric coupling. 相似文献
345.
I. Mukhopadhyay R. M. Lees W. Lewis-Bevan 《International Journal of Infrared and Millimeter Waves》1988,9(6):545-553
An assignment is proposed for the strong 127.0 m far-infrared (FIR) line of13CD3OH known to be pumped with very high efficiency by the 10P(8) CO2 laser line. On the basis of spectroscopic clues derived from calculated molecular parameters and energies for13CD3OH, the 127 m line is identified as the (nK,J)=(116,17)(125, 16) transition, and its companion 462.8 m line as the (116,17)(116,16) transition. Proposed partial assignments and predictions are also discussed for a number of other FIR laser lines in13CD3OH, CD3OH, CD3OD, CH3OD, CH3OH and13CH3OH. 相似文献
346.
347.
Christopher M. Liauw Viera Khunova Graham C. Lees Roger N. Rothon 《Macromolecular Symposia》2001,170(1):205-212
Interphase modification of impact modified isotactic poly(propene) (IMPP)/magnesium hydroxide (Mg(OH)2) composites, via use of the reactive modifier 1,3 phenylene dimaleimide (BMI) has led to the formation of composites that have strength and toughness more than twice that of the unmodified composite. These significant improvements in properties were found (via response surface analysis, DSC and matrix extraction‐DRIFTS studies) to be due to encapsulation of the filler particles with the elastomeric poly(ethene‐co‐propene) impact modifier phase of the IMPP. Acceptable processing characteristics can be realised together with excellent mechanical properties, via judicious addition of a lubricant (a fatty acid amide/ester blend) to the formulation. 相似文献