全文获取类型
收费全文 | 394篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
化学 | 198篇 |
晶体学 | 4篇 |
力学 | 8篇 |
数学 | 32篇 |
物理学 | 154篇 |
出版年
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 18篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 25篇 |
2007年 | 19篇 |
2006年 | 16篇 |
2005年 | 17篇 |
2004年 | 9篇 |
2003年 | 11篇 |
2002年 | 12篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1970年 | 2篇 |
1964年 | 2篇 |
1942年 | 4篇 |
1938年 | 2篇 |
1934年 | 3篇 |
1931年 | 2篇 |
1902年 | 2篇 |
1901年 | 2篇 |
排序方式: 共有396条查询结果,搜索用时 265 毫秒
31.
M. Della Negra D. Drijard H.G. Fischer G. Fontaine H. Frehse P. Frenkiel C. Chesquiere R. Gokieli P. Hanke W. Hofmann W. Isenbeck E.E. Kluge V. Korbel D. Linglin A. Minten A. Norton A. Putzer R. Sosnowski D. Wegener 《Physics letters. [Part B]》1976,65(4):394-396
The reaction pp→ppπ+π? at √s=31GeV was studied at the Split Field Magnet Facility of the CERN-ISR. Selecting events with two leading protons of x>0.9 and a rapidity gap Δy>2 between the protons and both pions a sample of 720 events is obtained representing a cross section of 25±10μb. The mass distribution of the dipion system, x and pT distributions for the protons are presented and analyzed for the presence of double pomeron exchange. 相似文献
32.
Richard E Norton 《Annals of Physics》1980,130(1):14-69
By extending methods previously used to study the equations of state at low temperature, it is shown that the entropy density and the statistical average of a conserved, non-spontaneously violated, charge density can be expanded in terms of integrals over products of many body n-point amplitudes defined for real, continuous frequencies. The general structure of the expansions is described, and it is demonstrated that essentially the same spectral function determines the entropy density and the average charge densities. Certain classes of terms are worked out in detail, and the formal sum of one such class is shown to provide the contributions to the equations of state arising from composite quasiparticles associated with the poles of the n-point amplitudes. [Another term, discussed in many previous works, involves the logarithms of the elementary propagators and yields the contributions to the equations of state coming from elementary quasiparticles.]The Appendices include an extensive study of the analytic properties of many body amplitudes in the frequencies of the external and internal lines. Specialized to zero temperature, these considerations apply to the Feynman diagrams for elementary particle amplitudes. 相似文献
33.
Salluzzo M Palomba F Pica G Andreone A Maggio-Aprile I Fischer O Cantoni C Norton DP 《Physical review letters》2000,85(5):1116-1119
We report on a study on the effect of Nd/Ba disorder on the ab-plane penetration depth of epitaxial Nd(1+x)Ba(2-x)Cu(3)O(7-delta) thin films. While in stoichiometric samples lambda(T) at low temperature is linear, Nd-rich films exhibit a quadratic law. For low Nd excess (x<0.04), a satisfying fit is obtained using the "dirty" d-wave model assuming that Nd ions at Ba sites act as strong scattering centers. At high x (x>0.15) the data are explained if Nd/Ba disorder becomes less effective as a source of scattering. The effect of localization has been discussed to account for the experimental results. 相似文献
34.
This paper presents a simulation and an analytical modeling of the machine interference problem in manufacturing cells. Each machine experiences two types of stoppage which are to be served by a robot. Several combinations of the distributions of the stoppages, service distributions, and service disciplines are studied. We determine the optimal number of machines assigned to the robot under different operating conditions such that the expected total cost of the manufacturing cell is minimized.This research is based on Mr. Norton's M.S. thesis, which was conducted at Rutgers. 相似文献
35.
Norton P. Peet 《Journal of heterocyclic chemistry》1989,26(3):713-716
A synthetic route to 5-substituted 3-(1H-tetrazol-5-yl)pyrazolo[1, 5-a]quinazolines is described. An unexpected displacement of a 4-morpholinyl group from the 5-position of this system occurred during tetrazole formation by the ammonia produced by in situ generation of hydrazoic acid from ammonium chloride and sodium azide. 相似文献
36.
G. W. Pearce L. B. Norton und P. J. Chapman 《Fresenius' Journal of Analytical Chemistry》1938,112(5-6):235-236
Ohne Zusammenfassung 相似文献
37.
38.
E. Nihoul G. Vortmann C. Meineke G. Lunge P. Naef Th. Salzer E. Kock W. Younger L. M. Norton M. Rosenbaum W. Spring Ed. Bourgeois N. Sokolow P. Maltschewski R. Otto C. Friedheim Fr. Stolba G. Linossier M. Lignon W. Gathorne Young R. Kayser H. Offermann A. Carnot V. Gasselin Th Petersen 《Analytical and bioanalytical chemistry》1896,35(1):200-211
39.
Yao S Hinds MG Murphy JM Norton RS 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,211(2):243-247
Conformational or chemical exchange can cause significant sensitivity loss in NMR spectroscopy through resonance broadening for nuclear spins involved in these processes. While this effect may sometimes be alleviated by manipulating experimental conditions such as temperature, pH, and buffers, conditions optimal for all resonances are not always achievable. As a consequence, any means of recovering or minimizing this exchange-induced sensitivity loss is potentially of significant value in regaining information otherwise lost. We report the experimental observation of significant sensitivity gain for nuclear spins undergoing chemical exchange with solvent (water) at exchange rates ca 1-10 s(-1) in (1)H-(15)N correlation spectra of proteins acquired with band-selective pulses (the SOFAST-HMQC sequence). 相似文献
40.
Liondas CA; Chrissoulidis DP 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(3):275-287
This paper is intended to clarify a misunderstanding concerningthe source singularity of the electric Green's tensor for aperfectly conducting semi-infinite cone of circular cross-section.Tai's series expansion of the Green's tensor is known to lacka singular term at the source region. Jones has reconstructedthe solution to this problem and has pointed out the differencebetween his result and that of Tai. The aim of our paper isto demonstrate that, although Jones's closed-form solution iscorrect, there is a mistake in his comparison with Tai's seriessolution. We conclude that one of the two additional singularterms that Jones claims as missing from Tai's formula must beomitted. Besides, we compare Jones's closed-form solution withSmyshlyaev's solution to the very same problem. We concludethat the magnetic field expressions given by Jones and Smyshlyaevcoincide, but a singular term is missing from Smyshlyaev's expressionfor the electric field. 相似文献