全文获取类型
收费全文 | 637篇 |
免费 | 11篇 |
专业分类
化学 | 350篇 |
晶体学 | 4篇 |
力学 | 28篇 |
数学 | 45篇 |
物理学 | 221篇 |
出版年
2022年 | 8篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2016年 | 13篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 25篇 |
2012年 | 24篇 |
2011年 | 25篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 22篇 |
2007年 | 20篇 |
2006年 | 24篇 |
2005年 | 23篇 |
2004年 | 22篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 21篇 |
1995年 | 9篇 |
1994年 | 15篇 |
1993年 | 19篇 |
1992年 | 25篇 |
1991年 | 8篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 17篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1982年 | 13篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1977年 | 19篇 |
1976年 | 7篇 |
1975年 | 15篇 |
1974年 | 11篇 |
1973年 | 17篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1968年 | 3篇 |
1967年 | 3篇 |
1928年 | 3篇 |
排序方式: 共有648条查询结果,搜索用时 15 毫秒
91.
92.
The effects of explicit Δ degrees of freedom on trinuclear binding energy and structure are investigated using the Argonne
V28Q Δ model. Separate dispersive effects, one- and two-Δ three-body force effects, and one- and two-Δ probabilities are determined
for the triton. Some new results are also given for the Hannover and Argonne V28 Δ models, and V28Q trinuclear Δ effects are
compared with those of these other models. Considerable consistency among the models is found, suggesting a coherent qualitative
picture of trinuclear Δ effects.
Received June 8, 1994; accepted for publication September 27, 1994 相似文献
93.
Seven laboratories took part in this interlaboratory study which was part of an investigation of the flame-speetrometric determination of potassium in rocks and minerals suitable for potassium-argon age-measurement. Three of these laboratories determined potassium in the following five international reference rocks: tonalite T-1, basalt BCR-1, andesite AGV-1, granite G-2, and granodiorite GSP-1. The other five samples (with the number of laboratories analysing them in parentheses) were: a chlorite rock (7), an altered basic igneous rock (5), an altered basaltic andesite (5), a biotite (6) and a potassium feldspar (7). Details of sample preparation and methods of analysis are given; no laboratory used exactly the same method as any of the other six laboratories. Results have been examined by analysis of variance; larger relative between- and within-laboratory variations occurred for the two samples containing less than 0.1% potassium than for seven of the eight other (higher potassium) samples; between-laboratory variations for the basalt BCR-1 and, to a lesser extent, the andesite AGV-1, were high and of similar magnitude to those for the samples containing less than 0.1% potassium. The causes of any poor interlaboratory agreement in the present study are considered. 相似文献
94.
J.R. Rice 《Journal of the mechanics and physics of solids》1978,26(2):61-78
Restrictions on the quasi-static extension, or healing, of Griffith cracks are developed in the framework of irreversible thermodynamics. It is emphasized that thermodynamics requires that (G ? 2γ)ι ? 0, where ι is crack speed, G the Irwin energy release rate, and 2γ the work of reversible separation of the surfaces to be fractured. Implications for ‘lattice trapping’ models of cracks and for thermally-activated crack motion are discussed, as are the effects on crack growth and healing of a surface-reactive environment, in which case γ must be given a definition appropriate to adsorption-altered surface properties. 相似文献
95.
Periodic disruptions were observed which persisted for as long as 400 ms during plasma discharges. Soft X-ray emissions, Te, ne, impurity radiation and plasma position showed the pulsations. The abrupt collapse in X-ray signal (1–2 ms; period ∽10 ms) encompassed a large fraction of the plasma cross section. Plasma conditions associated with the onset of this pattern are examined. 相似文献
96.
Several quantum mechanical calculations of differential cross sections for elastic scattering of electrons by H2 are compared with the recent experiments by Williams. 相似文献
97.
Theoretical equilibrium geometries for ketenimine, aminoacetylene and ethynol have been obtained using the MP3/6-31G** ab initio method. Empirical scaling factors have been introduced to estimate the rotational constants Ao, Bo and Co. In addition the complete harmonic force fields for ketenimine, ketene and diazomethane have been computed, normal coordinate analyses have been performed and the quartic centrifugal distortion constants estimated. 相似文献
99.
100.
D.A. Evans E.L. Hart R.M. Rice R.B. Bacastow S.Y. Fung S.S. Hertzbach R. Ponte J. Button-Shafer S.S. Yamamoto 《Nuclear Physics B》1977,119(2):315-333
Results are presented of a study of the reaction K?p→Λπ+π? in the c.m. energy region of 1.65 to 1.72 GeV. Dalitz plots indicate that the reaction proceeds primarily through the intermediate states Σ?(1385)π+ and Σ?(1385)π+, but the resonance bands intersect inside the kinematic ellipse and a simple quasi-two-body interpretation is not possible. Legendre coefficients are presented for the angular distributions of the Λπ+ and Λπ? sub-systems in the overall c.m. frame. Analogous coefficients as suggested by Deler and Valladas, which describe the angular distribution of the final three-body state are also presented. 相似文献