全文获取类型
收费全文 | 152篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 99篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 9篇 |
物理学 | 49篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 8篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 31 毫秒
81.
Calabrese V Quici S Rossi E Cariati E Dragonetti C Roberto D Tordin E De Angelis F Fantacci S 《Chemical communications (Cambridge, England)》2010,46(44):8374-8376
7-N,N-Dibutylamino-2-azaphenanthrene (L(3)), 8-N,N-dibutylamino-2-azachrysene (L(4)) and related Ir(i) complexes or alkylated salts show high second-order NLO responses, as determined by the EFISH technique and DFT calculations. L(4) is appealing as building block for NLO active materials due to its unexpected large μβ(1.907)value and its very high thermal stability. 相似文献
82.
MR Imaging of total hip arthroplasty: comparison among sequences to study the sciatic nerve at 1.5 T
Alberto Tagliafico Andrea Podestà Andrea Assini Leonardo Boccacini Giovanni Serafini Massimo Calabrese Carlo Martinoli 《Magnetic resonance imaging》2010
Purpose
This study was done to test a series of MR sequences for evaluating the sciatic nerve after total hip arthroplasty (THA).Material and Methods
The study protocol was approved by the institutional review board. Informed consent was obtained from all patients. Twenty-five patients (11 men and 14 women mean age: 62.3±5.7 years) with THA were included in this prospective study. MRI protocol included sequences that were preliminarily tailored for nerve imaging in patients with THA: proton density (PD)-weighted turbo SE, T1-weighted turbo SE (TSE) 3 mm thickness, T1-weighted turbo SE (TSE) 6 mm thickness, T1-weighted turbo SE with high bandwidth (TSE hBW), T2- weighted TSE, T2-weighted with fat saturation and short-tau inversion recovery (STIR). For each sequence, we evaluated the visibility of the sciatic nerve using a semiquantitative score (0=total masking; 1=insufficient visibility; 2=sufficient visibility; 3=optimal visibility). The sum of the scores given to each sequence was divided by the maximal sum, obtaining a percentage visibility index. Friedman and sign tests were used for statistical analysis.Results
MR examination time was approximately 40 min. No patients reported pain, heat or symptoms related to nerve stimulation. The visibility index ranged between 88% and 70% for the first four sequences. The T1-weighted TSE hBW sequence had the best visibility index (P<.05). The visibility indexes of the first four sequences were significantly higher (P<.004, sign test) than those of the remaining three sequences.Conclusion
The sciatic nerve could be studied at 1.5 T in patients following THA. The nerve is better visualized with T1-weighted TSE hBW sequences. On T2-weighted sequences and STIR, the visibility of the nerve is low. 相似文献83.
84.
S.N. Atutov V. Biancalana R. Calabrese T. Clauser R. Grimm V. Guidi G. Lamanna I. Lauer P. Lenisa V. Luger E. Mariotti L. Moi U. Schramm V. Stagno M. Stößel L. Tecchio V. Variale 《Hyperfine Interactions》1998,115(1-4):47-52
“White-light” cooling of an ion beam confined in a storage ring has been demonstrated at Test Storage Ring in Heidelberg.
Measurements aimed at comparing “white-light” with single-mode laser cooling show that “white-light” cooling gives lower temperatures
at higher ion densities both in a coasting and in a bunched beam.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
85.
S.N. Atutov V. Biancalana R. Calabrese V. Guidi P. Lenisa B. Mai E. Mariotti L. Moi L. Tomassetti 《Hyperfine Interactions》2000,127(1-4):503-506
A frequency comb in the UV region with a bandwidth greater than 100 MHz is generated by successive frequency shifts of a single
mode laser by an acousto-optic modulator coupled to a passive ring cavity. The obtained spectrum is particularly suitable
for laser cooling when a large velocity capture range is required as in the case, for example, of ions confined in a storage
ring.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
86.
L. Tecchio G. Bisoffi G. Ciullo A. Dainelli S. Gustafsson M.F. Moisio A. Pisent M. Poggi B. Yang A. Burov N.S. Dikansky D.V. Pestrikov V.V. Parkhomchuk R. Calabrese V. Guidi P. Lenisa T. Clauser G. Lamanna M. Rutigliano V. Stagno V. Variale G. Di Massa M.R. Masullo V.G. Vaccaro C. Marinelli E. Mariotti L. Moi 《Hyperfine Interactions》1997,108(1-3):355-372
After the successful exploitation of electron cooling in several heavy ion storage rings the possibility of generating crystalline
ion beams gained the interest of particle accelerator physicists. New cooling methods, such as laser cooling, give further
opportunity to reach ultra cold system of particles necessary for the state transition to the crystalline configuration. Crystalline
beams will give insight into a completely new research field, reaching higher standards in precision measurements and techniques.
The applicative potentialities of crystalline beams justify a careful investigation on this subject.
The conceptual design of a low-energy heavy-ion storage ring, called CRYSTAL, proposed for the experimental demonstration
of crystalline beams at Legnaro LNL is presented.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
87.
Gosetti F Chiuminatto U Mazzucco E Robotti E Calabrese G Gennaro MC Marengo E 《Journal of chromatography. A》2011,1218(37):6308-6318
An on-line solid phase extraction (SPE) ultra high performance liquid chromatography tandem mass spectrometry method has been developed for the simultaneous identification and determination of thirteen polycyclic aromatic hydrocarbons (PAHs) and twelve aldehydes (derivatized with 2,4-dinitrophenylhydrazine). The chromatographic conditions have been optimized to obtain the maximum of sensitivity and resolution taking into account the different retention interactions and the different ionization conditions of PAHs and derivatized aldehydes. LOD values ranging from 0.028 to 0.768 μg L(-1) for PAHs and from 0.002 to 0.125 μg L(-1) for aldehydes were obtained. The resolution permitted the separation of four couples of PAH isomers. Sample pre-treatment and SPE were optimized in order to apply the whole methodology to the analysis of different food matrices as salmon, frankfurter, steak, and pork chop, subjected to different cooking modes (smoked, grilled, cooked in oil or in butter). Particular attention was devoted to the evaluation of matrix effect that was significantly reduced through the on-line SPE treatment. For each food matrix the method detection limits, the method quantitation limits, and the recovery R were evaluated. R was shown not to depend on analyte concentration in the explored concentration range (LOQ - 50.000 μg L(-1)): the average R percent ranges from 70.6% to 120.0%. 相似文献
88.
Maria Teresa Cambria Santa Ragusa Vittorio Calabrese Antonio Cambria 《Applied biochemistry and biotechnology》2011,163(3):415-422
The white rot fungus Rigidoporus lignosus produces substantial amounts of extracellular laccase, a multicopper blue oxidase which is capable of oxidizing a wide range
of organic substrates. Laccase production can be greatly enhanced in liquid cultures supplemented with various aromatic and
phenolic compounds. The maximum enzyme activity was reached at the 21st or 24th day of fungal cultivation after the addition
of inducers. The zymograms of extracellular fluid of culture preparation in the presence of inducers, at maximum activity
day, revealed two bands with enzymatic activity, called Lac1 and Lac2, having different intensities. Lac2 band shows the higher
intensity which changed with the different inducers. Laccase induction can be also obtained by adding to the culture medium
olive mill wastewaters, which shows a high content of phenolic compounds 相似文献
89.
Juan M. Manriquez Michael D. Ward Joseph C. Calabrese Paul J. Fagan Arthur J. Epstein Joel S. Miller 《Molecular Crystals and Liquid Crystals》2013,570(1):527-534
The synthesis and physical properties of meta- and para-bis(metallocene) benzene complexes with M = Fe, Co, Ni are reported. The electrochemical properties suggest greater electronic interaction between metal centers in the para-M complexes. In addition, the magnetic properties suggest different degrees of spin exchange for the meta and para complexes, with the latter exhibiting more pronounced antiferromagnetic coupling. These molecular complexes are considered prototypes for extended metallocene polymers. 相似文献
90.
U. Klabunde R. Mulhaupt T. Herskovitz A. H. Janowicz J. Calabrese S. D. Ittel 《Journal of polymer science. Part A, Polymer chemistry》1987,25(7):1989-2003
Abstraction of phosphine from the nickel(II) P, O-chelated complexes, Ni[Ph2PCH?C(Ph)O] (Ph)(PPh3), and related species converts them from olefin oligomerization to olefin polymerization catalysts. Phosphine acceptors such as Rh(acetylacetonate)(C2H4)2 or Ni(1,5-cyclooctadiene)2 are most effective. Alternatively, nickel complexes in which the phosphine ligand is replaced with weakly coordinated pyridine can be prepared. These active, homogeneous catalysts can be tuned to give either low or high molecular weight, linear low or high density polyethylene. Depending on the diluent, the same catalytic complex can be used as heterogeneous or homogeneous catalyst. They are tolerant of oxygenated, hydroxylic, or polar molecules that would poison normal early transition metal-based Ziegler-Natta catalysts. In fact, the polymerizations can be run in solvents such as ethanol or acetone, but hydrocarbon solvents are preferred. 相似文献