全文获取类型
收费全文 | 246篇 |
免费 | 5篇 |
国内免费 | 3篇 |
专业分类
化学 | 134篇 |
力学 | 11篇 |
数学 | 20篇 |
物理学 | 89篇 |
出版年
2015年 | 7篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1988年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1974年 | 4篇 |
1955年 | 2篇 |
1938年 | 4篇 |
1937年 | 7篇 |
1936年 | 3篇 |
1935年 | 4篇 |
1934年 | 4篇 |
1933年 | 2篇 |
1932年 | 2篇 |
1931年 | 2篇 |
1930年 | 4篇 |
1928年 | 2篇 |
1927年 | 2篇 |
1926年 | 7篇 |
1925年 | 3篇 |
1924年 | 6篇 |
1923年 | 6篇 |
1922年 | 3篇 |
1921年 | 7篇 |
1920年 | 3篇 |
1917年 | 2篇 |
排序方式: 共有254条查询结果,搜索用时 31 毫秒
61.
F. Hinterberger F. Bauer J. Bisplinghoff K. Büer M. Busch T. Colberg L. Demirrs C. Dahl P. D. Eversheim O. Eyser O. Felden R. Gebel J. Greiff E. Jonas H. Krause C. Lehmann J. Lindlein R. Maier A. Meinerzhagen C. Pauli D. Prasuhn H. Rohdje D. Rosendaal P. Von Rossen N. Schirm W. Scobel K. Ulbrich E. Weise T. Wolf R. Ziegler 《Progress in Particle and Nuclear Physics》2003,50(2):537-546
Excitation functions of the differential cross sections dσ/dgw, analyzing powers AN and spin correlation parameters ANN, ASS and ASL have been measured with internal targets at the Cooler Synchrotron COSY. Data were taken continously during the acceleration and deceleration of the internal beam for kinetic energies between 450 and 2500 MeV and scattering angles 30° σcm 90°. Details of the experimental method are presented. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures are found. Upper limits on the coupling of narrow resonances to elastic scattering in the mass range √s = 2.2…2.8 GeV are deduced. The data have significant impact on phase shift solutions. 相似文献
62.
Cognitive level in problem segments and theory segments 总被引:1,自引:0,他引:1
Barbara Drollinger-Vetter Frank Lipowsky Christine Pauli Kurt Reusser Eckhard Klieme 《ZDM》2006,38(5):399-412
Problems play an important role in mathematics instruction and are therefore frequently seen as central points of application for measures of instructional development. The research project “Quality of instruction and mathematical understanding in different cultures” examines the cognitive level of practice problems and theory problems in a three-lesson unit on the Introduction to Pythagorean theorem1: Analogously to the TIMSS 1999 video study, a differentiation was made between the cognitive level of problem statement and the cognitive level of problem implementation. Additionally, the lesson time was also divided into practice and theory segments. The results show that teachers with a high proportion of connection activities in practice segments do not necessarily also spend a greater proportion of time on an analogous level for theory. 相似文献
63.
64.
Agnello M Belli G Bendiscioli G Bertin A Botta E Bressani T Bruschi M Bussa MP Busso L Calvo D Cereda B Cerello PG Cicalò C Corradini M Costa S De Castro S Donzella A Feliciello A Ferrero L Filippi A Filippini V Fontana A Galli D Garfagnini R Giacobbe B Gianotti P Grasso A Guaraldo C Iazzi F Lanaro A Lodi Rizzini E Lucherini V Marcello S Marconi U Masoni A Minetti B Montagna P Morando M Nichitiu F Panzieri D Pauli G Piccinini M Puddu G Rossetto E Rotondi A Rozhdestvensky AM Saino A Salvini P 《Physical review letters》1995,74(3):371-374
65.
C. Pigot J.P. de Brion A. Caillet J.B. Cheze J. Derre G. Marel E. Pauli G. Vrana G. dAgostini G. Auriemma G. Marini G. Martellotti F. Massa A. Nigro A. Rambaldi A. Sciubba S. Reucroft E.G.H. Williams 《Nuclear Physics B》1985,249(1):172-188
The production of a strange dibaryonic system called H+1 (M = 2.13 GeV/c2, S = ?1), has been studied with a missing mass spectrometer, at the CERN Proton Synchrotron, in the reaction K?d → π?H+1 and in the line-reversed reaction π+d → K+H+1 between 0.9 and 1.4 GeV/c.The reactions , ,have been studied in a missing mass spectrometer at CERN. The experiment (PS159) is well adapted to search for a signal in the missing mass X+ (B = 2, S = ?1) produced in the backward c.m.s. direction, between 2.0 and 2.3 GeV/c2. The two reactions have been analysed at three different beam settings: 1.4, 1.06 and 0.92 GeV/c for reaction (1) and 1.4, 1.2 and 1.06 GeV/c for reaction (2). 相似文献
66.
Zusammenfassung Als letzte Fehlerquelle der Alkylimidbestimmung wird die gerätetechnische Seite besprochen. Vor allem das lange aufsteigende Siederohr der bisher gebräuchlichen Gerätetypen führt unter Erschwerung des Abtransportes der Reaktionspartner bzw. des Reaktionsproduktes zu physikalisch-chemischen Vorgängen, die namentlich bei höheren Temperaturen durch thermische Zersetzung von Alkyljodid unkontrollierbare Analysendefizite bedingen.Es wird ein neues einf aches Gerät zur Alkylimidbestimmung angegeben, das unter Vermeidung gerätetechnischer Fehlerquellen auch eine Veringerung des Gesamtinnenvolumens aufweist und dadurch eine wesentliche Verkürzung der Analysendauer ermöglicht.
Die gerätetechnische Seite als mögliche Fehlerquelle der Mikro-Alkylimidbestimmung; gleichzeitig Angabeeinesneuen vereinfachten Gerätes. 相似文献
Summary The apparative-technical side has been discussed as the final source of error in the alkyl imide determination. Above all, the ascending boiling tube of the types of apparatus used hitherto leads, because of impeding the carrying away of the reactants or of the reaction products, to physical-chemical processes, which especially at higher temperatures result in uncontrollable analysis deficits because of thermal decomposition of alkyl iodide.A new simple apparatus is described for the determination of alkyl imide. It avoids the sources of error stemming from faults in the design of the apparatus. Because of the lessened total internal volume, it makes possible a significant shortening of the time required for an analysis.
Résumé Comme dernière cause d'erreur dans le dosage des alcoylimides on envisage les défauts techniques des appareils. En particulier le long tuyau vertical que portent les appareils utilisés jusqu'à ce jour produit une augmentation des transports de substances entrant en réaction (donc des produits formés) et par suite, des phénomènes physico-chimiques qui, surtout à haute température, entrainent une décomposition thermique de l'iodure d'alcoyle conduisant à des pertes incontrôlables dans l'analyse.On décrit un nouvel appareil simple qui, en supprimant les erreurs dues à l'appareil, diminue le volume intérieur total et permet une analyse bien plus rapide.
Die gerätetechnische Seite als mögliche Fehlerquelle der Mikro-Alkylimidbestimmung; gleichzeitig Angabeeinesneuen vereinfachten Gerätes. 相似文献
67.
J. Pauli G. Scheying C. Mügge A. Zschunke P. Lorenz 《Fresenius' Journal of Analytical Chemistry》1997,357(5):508-513
The quantitative characterization of macro-porous materials with regard to pore width and pore width distribution was accomplished
for the first time by using 1H-NMR microscopy in combination with suitable methods of digital image analysis. Here we present the newly developed algorithm
and discuss the first experimental results. Large-pored glass filter systems filled with silicon oil as intrusion fluid were
used as references. Silicates of unknown pore width were analyzed both with the new method and with Hg intrusion. NMR image
data were recorded using a 3D spin echo sequence, which gave 128 slice images with a spatial resolution of 14.5 μm × 14.5
μm within each slice, with a slice-thickness of 37 μm or 48 μm. A quantitative evaluation of the 3D NMR data, with regard
to pore width and pore width distribution, was done using the appropriate image processing function of the HORUS program.
Individual slice evaluation was performed first, followed by an analysis of the binding elements between the slices. Pore
widths of the glass filters determined using this analytical algorithm were in accordance with the manufacturer’s values,
and silicate pore widths were in good agreement with the values determined by Hg intrusion.
Received: 4 June 1996 / Revised: 12 August 1996 / Accepted: 15 August 1996 相似文献
68.
Ohne Zusammenfassung 相似文献
69.
70.