全文获取类型
收费全文 | 170篇 |
免费 | 0篇 |
专业分类
化学 | 19篇 |
力学 | 4篇 |
数学 | 22篇 |
物理学 | 125篇 |
出版年
2021年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2013年 | 5篇 |
2012年 | 15篇 |
2011年 | 25篇 |
2010年 | 5篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 10篇 |
2005年 | 14篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1987年 | 3篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1915年 | 1篇 |
排序方式: 共有170条查询结果,搜索用时 31 毫秒
91.
We have used x-ray magnetic circular dichroism, which offers a unique capability to give element specific information at submonolayer sensitivity, to determine the spin and orbital magnetic moments at the Fe/GaAs(100) interface. The wedge samples, grown by molecular beam epitaxy at room temperature, consisted of 0.25-1 monolayer (ML) Fe on GaAs(100)-4x6 capped with 9 ML Co and have shown Fe spin moments of (1.84-1.96)micro(B) and a large orbital enhancement. Our results demonstrate unambiguously that the Fe/GaAs(100)-4x6 interface is ferromagnetic with a bulklike spin moment, which is highly promising for spintronics applications. 相似文献
92.
Adams J Adler C Aggarwal MM Ahammed Z Amonett J Anderson BD Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellwied R Berger J Bezverkhny BI Bharadwaj S Bhatia VS Bichsel H Bland LC Blyth CO Bonner BE Botje M Boucham A Brandin A Bravar A Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Carroll J Castillo J Cebra D Chaloupka P Chattopdhyay S Chen HF Chen Y Cheng J Cherney M Chikanian A Christie W Coffin JP Cormier TM Cramer JG Crawford HJ 《Physical review letters》2004,92(18):182301
The transverse mass spectra and midrapidity yields for Xis and Omegas are presented. For the 10% most central collisions, the (-)Xi(+)/h(-) ratio increases from the Super Proton Synchrotron to the Relativistic Heavy Ion Collider energies while the Xi(-)/h(-) stays approximately constant. A hydrodynamically inspired model fit to the Xi spectra, which assumes a thermalized source, seems to indicate that these multistrange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to pi, K, p, and Lambdas. 相似文献
93.
[structure] Various substituted pyridines can be prepared regioselectively by a sequence involving an intramolecular thermal or high-pressure Diels-Alder cycloaddition of an oximino malonate dienophile tethered to a dienic carboxylic acid, followed by mild aromatization of the resulting cycloadduct with cesium carbonate in DMF at room temperature. 相似文献
94.
Lebedev SV Beg FN Bland SN Chittenden JP Dangor AE Haines MG Pikuz SA Shelkovenko TA 《Physical review letters》2000,85(1):98-101
We present the first measurements by x-ray radiography of the development of instabilities during the implosion phase of wire array Z pinches. The seeding of perturbations on the dense core of each wire is provided by nonuniform sweeping of the low-density coronal plasma from the cores by the global JxB force. The spatial scale of these perturbations ( approximately 0.5 mm for Al and approximately 0.25 mm for W) is determined by the size of the wire cores ( approximately 0.25 mm for Al and approximately 0.1 mm for W). A qualitative change in implosion dynamics, with transition to 0D-like trajectory, was observed in Al arrays when the ratio of interwire gap to wire core size was decreased to approximately 3. 相似文献
95.
Lebedev SV Aliaga-Rossel R Bland SN Chittenden JP Dangor AE Haines MG Zakaullah M 《Physical review letters》2000,84(8):1708-1711
Two different modes of nested wire array implosion driven by a 1-MA, 240-ns current pulse were observed, determined by the fraction of total current induced in the inner array. Penetration by the outer array through the inner with switching of current occurred if current in the inner array was initially suppressed. Simultaneous implosion of arrays with apparent compression of magnetic flux between the arrays was observed if approximately 20% of the current was in the inner array. In both cases the x-ray pulse rise time of approximately 10 ns (for 260-ns implosion time) was considerably smaller than for a single array. 相似文献
96.
Abelev BI Aggarwal MM Ahammed Z Anderson BD Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Baumgart S Belaga VV Bellingeri-Laurikainen A Bellwied R Benedosso F Betts RR Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth SL Bombara M Bonner BE Botje M Bouchet J Brandin AV Burton TP Bystersky M Cai XZ Caines H Calderón de la Barca Sánchez M Callner J Catu O Cebra D Cervantes MC Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH Chen JY 《Physical review letters》2007,99(14):142003
We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (-1< or = eta < or = +2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering. We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in semi-inclusive deep inelastic scattering and forward hadron production in pp collisions. 相似文献
97.
An unprecedented polyborate ester anion: X-ray diffraction studies on [1,8-C10H6(NMe2)2H][B5O6(OMe)4
The slow hydrolysis of B(OMe)3 in a CH2Cl2 solution in the presence of 1,8-C10H6(NMe2)2 (5:1 ratio) led to the formation of the novel isolated pentaborate ester anion [B5O6(OMe)4]-, which was characterized by a single-crystal X-ray diffraction study as the salt [1,8-C10H6(NMe2)2H][B5O6(OMe)4]. 相似文献
98.
Harvey-Thompson AJ Lebedev SV Patankar S Bland SN Burdiak G Chittenden JP Colaitis A De Grouchy P Doyle HW Hall GN Khoory E Hohenberger M Pickworth L Suzuki-Vidal F Smith RA Skidmore J Suttle L Swadling GF 《Physical review letters》2012,108(14):145002
A Thomson scattering diagnostic has been used to measure the parameters of cylindrical wire array Z pinch plasmas during the ablation phase. The scattering operates in the collective regime (α>1) allowing spatially localized measurements of the ion or electron plasma temperatures and of the plasma bulk velocity. The ablation flow is found to accelerate towards the axis reaching peak velocities of 1.2-1.3×10(7) cm/s in aluminium and ~1×10(7) cm/s in tungsten arrays. Precursor ion temperature measurements made shortly after formation are found to correspond to the kinetic energy of the converging ablation flow. 相似文献
99.
Aaltonen T Albrow MG Alvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel JA Arisawa T Artikov A Asaadi J Ashmanskas W Auerbach B Aurisano A Azfar F Badgett W Bae T Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauce M Bedeschi F Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Bisello D Bizjak I Bland KR Blumenfeld B Bocci A Bodek A Bortoletto D Boudreau J Boveia A Brigliadori L Bromberg C Brucken E Budagov J Budd HS Burkett K 《Physical review letters》2012,108(8):081801
We have observed exclusive γγ production in proton-antiproton collisions at √s=1.96 TeV, using data from 1.11±0.07 fb(-1) integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E(T)>2.5 GeV and pseudorapidity |η|<1.0, with no other particles detected in -7.4<η<+7.4. The two showers have similar E(T) and azimuthal angle separation Δφ~π; 34 events have two charged particle tracks, consistent with the QED process ppˉ→p+e(+)e(-)+pˉ by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive π(0)π(0) is consistent with zero and is <15 at 95% C.L. The cross section for ppˉ→p+γγ+pˉ with |η(γ)|<1.0 and E(T)(γ)>2.5 GeV is 2.48(-0.35)(+0.40)(stat)(-0.51)(+0.40)(syst) pb. 相似文献
100.
Agakishiev G Aggarwal MM Ahammed Z Alakhverdyants AV Alekseev I Alford J Anderson BD Anson CD Arkhipkin D Averichev GS Balewski J Barnby LS Beavis DR Bellwied R Betancourt MJ Betts RR Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Bordyuzhin IG Borowski W Bouchet J Braidot E Brandin AV Brovko SG Bruna E Bueltmann S Bunzarov I Burton TP Cai XZ Caines H Sánchez MC Cebra D Cendejas R Cervantes MC Chaloupka P Chattopadhyay S Chen HF Chen JH Chen JY Chen L Cheng J Cherney M Chikanian A 《Physical review letters》2012,108(7):072302
We report transverse momentum (p(T)≤15 GeV/c) spectra of π(±), K(±), p, p[over ˉ], K(S)(0), and ρ(0) at midrapidity in p+p and Au+Au collisions at √S(NN)=200 GeV. Perturbative QCD calculations are consistent with π(±) spectra in p+p collisions but do not reproduce K and p(p[over ˉ]) spectra. The observed decreasing antiparticle-to-particle ratios with increasing p(T) provide experimental evidence for varying quark and gluon jet contributions to high-p(T) hadron yields. The relative hadron abundances in Au+Au at p(T)?8 GeV/c are measured to be similar to the p+p results, despite the expected Casimir effect for parton energy loss. 相似文献