全文获取类型
收费全文 | 594篇 |
免费 | 33篇 |
国内免费 | 6篇 |
专业分类
化学 | 457篇 |
力学 | 11篇 |
数学 | 73篇 |
物理学 | 92篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 26篇 |
2012年 | 40篇 |
2011年 | 50篇 |
2010年 | 31篇 |
2009年 | 19篇 |
2008年 | 38篇 |
2007年 | 37篇 |
2006年 | 38篇 |
2005年 | 30篇 |
2004年 | 15篇 |
2003年 | 19篇 |
2002年 | 21篇 |
2001年 | 26篇 |
2000年 | 14篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1980年 | 2篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1965年 | 1篇 |
1961年 | 2篇 |
排序方式: 共有633条查询结果,搜索用时 0 毫秒
61.
A. Breakstone R. Campanini H. B. Crawley M. Cuffiani G. M. Dallavalle M. M. Deninno K. Doroba D. Drijard F. Eabbri A. Firestone H. G. Fischer H. Frehse W. Geist H. Flöge L. Gesswein G. Giacomelli R. Gokieli M. Gorbics M. Gorski P. Hanke M. Heiden W. Herr D. Isenhower E. E. Kluge J. W. Lamsa T. Lohse R. Mankel W. T. Meyer T. Nakada M. Panter A. Putzer K. Rauschnabel B. Rensch E. Rimondi M. Schmelling G. P. Siroli R. Sosnowski M. Szczekowski O. Ullaland D. Wegener R. Yeung 《Zeitschrift fur Physik C Particles and Fields》1987,33(4):475-481
Gluon scattering processes are studied in hadronic highp T events using data obtained with the Split Field Magnet detector (SFM) at the CERN ISR. The experimental set-up allowed the scanning of a wide range of parton energies and scattering angles. It is shown that for positive pions as trigger particles, the parton composition of the recoil jet is correlated with the polar angle and transverse momentum of the triggering pion. Over the kinematical region studied, the recoil jet originates predominantly from scatered gluons, with an increasing prevalence of the gluon component towards forward triggering angles. The variation of the momentum structure of the recoil jet with the trigger angle indicates that the fragmentation function of gluons is softer than that of quarks. 相似文献
62.
The paradigm of randomly-furcating stochastic differential games incorporates additional stochastic elements via randomly branching payoffs in stochastic differential games. This paper considers dynamically stable cooperative solutions in randomly furcating stochastic differential games. Analytically tractable payoff distribution procedures contingent upon specific random realizations of the state and payoff structure are derived. This new approach widens the application of cooperative differential game theory to problems where the evolution of the state and future environments are not known with certainty. Important cases abound in regional economic cooperation, corporate joint ventures and environmental control. An illustration in cooperative resource extraction is presented. 相似文献
63.
Readily available arabinose-derived 4-uloses, containing a tunable butane-2,3-diacetal as the steric sensor, displayed increasing enantioselectivity (up to 93% ee) with the size of the acetal alkyl group in catalytic asymmetric epoxidation of trans-disubstituted and trisubstituted alkenes. 相似文献
64.
65.
Samples of ions are studied by non-suppressed ion chromatography and an ultraviolet absorbance detector. When two eluents of similar properties but different absorptivities per normal concentration are used in succession, two distinct chromatograms are obtained for the same sample. This information can be used to predict the number of equivalents of each ion present, as well as its absorptivity. In conjunction with elution-time studies, molar concentrations can also be obtained. The procedure does not require knowledge of the identity or any physical properties of the ionic species, and is applicable to ions with arbitrary absorption strengths. 相似文献
66.
R. Ködding W. Lamprecht H. P. Wolff J. Karl und KH. R. Koczorek 《Fresenius' Journal of Analytical Chemistry》1961,181(1):574-580
Ohne ZusammenfassungAuszug aus der Dissertation Reinhard Ködding, Technische Hochschule München 1961. 相似文献
67.
Kinetics studies of the OH-initiated oxidation of 2-butyne, propyne, and acetylene were conducted at 100 Torr and 298 K using turbulent flow chemical ionization mass spectrometry. The major oxidation products were identified, and with the aid of supporting electronic structure thermodynamics calculations, a general OH-initiated oxidation mechanism for the alkynes is proposed. The major product branching ratio and the product-forming rate constants for the 2-butyne-OH adduct + O(2) reaction were experimentally determined as well. The atmospheric implications of the chemical oxidation mechanism and kinetics results are discussed. 相似文献
68.
The effects of finite grid resolution on the statistics of small scales in direct numerical simulations of turbulent mixing of passive scalars are addressed in this paper. Simulations at up to 20483 grid points with grid spacing Δx varied from about 2 to 1/2 Batchelor scales (ηB) show that most conclusions on Schmidt number (Sc) dependence from prior work at less stringent resolution remain qualitatively correct, although simulations at resolution Δx≈ηB are preferred and will give adequate results for many important quantities including the scalar dissipation intermittency exponent and structure functions at moderately high orders. For Sc≥1, since ηB=ηSc−1/2 (where η is the Kolmogorov scale), the requirement Δx≈ηB is more stringent than the corresponding criterion Δx≈η for the velocity field, which is thus well resolved in simulations aimed at high Schmidt number mixing. A simple argument is given to help interpret the effects of Schmidt and Reynolds numbers on trends towards local isotropy and saturation of intermittency at high Schmidt number. The present results also provide evidence for a trend to isotropy at high Reynolds number with fixed Sc=1.0. This is a new observation apparently not detected in less well resolved simulations in the past, and will require further investigation in the future. 相似文献
69.
Willie Wai Yeung Wong 《Archiv der Mathematik》2018,110(3):273-289
We prove the pointwise decay of solutions to three linear equations: (1) the transport equation in phase space generalizing the classical Vlasov equation, (2) the linear Schrödinger equation, (3) the Airy (linear KdV) equation. The usual proofs use explicit representation formulae, and either obtain \(L^1\)—\(L^\infty \) decay through directly estimating the fundamental solution in physical space or by studying oscillatory integrals coming from the representation in Fourier space. Our proof instead combines “vector field” commutators that capture the inherent symmetries of the relevant equations with conservation laws for mass and energy to get space–time weighted energy estimates. Combined with a simple version of Sobolev’s inequality this gives pointwise decay as desired. In the case of the Vlasov and Schrödinger equations, we can recover sharp pointwise decay; in the Schrödinger case we also show how to obtain local energy decay as well as Strichartz-type estimates. For the Airy equation we obtain a local energy decay that is almost sharp from the scaling point of view, but nonetheless misses the classical estimates by a gap. This work is inspired by the work of Klainerman on \(L^2\)—\(L^\infty \) decay of wave equations, as well as the recent work of Fajman, Joudioux, and Smulevici on decay of mass distributions for the relativistic Vlasov equation. 相似文献
70.
Fan Yan Alan K.H. Yeung Guanrong Chen 《Communications in Nonlinear Science & Numerical Simulation》2013,18(9):2515-2526
This paper reports a numerical study of energy consumption and time efficiency of sensor networks with five different structural topologies and four different routing methods, regarding their performances and costs, which might provide some references and guidelines for designing sensor networks under various conditions for possible applications. 相似文献