全文获取类型
收费全文 | 401篇 |
免费 | 4篇 |
专业分类
化学 | 173篇 |
晶体学 | 5篇 |
力学 | 20篇 |
数学 | 39篇 |
物理学 | 168篇 |
出版年
2022年 | 5篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 13篇 |
2012年 | 24篇 |
2011年 | 22篇 |
2010年 | 19篇 |
2009年 | 11篇 |
2008年 | 16篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 22篇 |
2004年 | 20篇 |
2003年 | 9篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1989年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1978年 | 5篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 7篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1946年 | 2篇 |
1945年 | 2篇 |
1944年 | 2篇 |
1943年 | 6篇 |
排序方式: 共有405条查询结果,搜索用时 15 毫秒
371.
A selective and sensitive method for the extraction and spectrophotometric determination of vanadium(V) in microgram quantities is described. The molar absorptivity of the yellow vanadium(V)-caffeic acid-Aliquat 336 extract is 1.3 x 10(4) 1.mole(-1).cm(-1) at 370nm. The method is compared with the atomic-absorption spectrometric method and applied to the trace determination of vanadium in steel, alloys, a rock and environmental samples. 相似文献
372.
373.
A. S. Menon 《Colloid and polymer science》1936,76(1):9-15
Ohne Zusammenfassung
übersetzt von A. Siehr (Leipzig).
Der Verfasser dankt bei dieser Gelegenheit Herrn Prof. H. E. Watson, D. Sa, F. I. C., M. I. Chem. E. für die zahlreichen wertvollen
Anregungen und für die f?rdernde Kritik w?hrend der Durchführung dieser Arbeit. 相似文献
374.
375.
We propose an iterative scheme to compute quasi-analytically the laser irradiance transmitted through a turbid media illuminated by high-frequency intensity-modulated light. We compare the spatial distribution of the transmitted signal obtained from iterative calculations with that obtained from random walk simulations and from the traditional diffusion theory. In the regime where the diffusion theory breaks down for a highly modulated source, only the ballistic and quasi-ballistic photons survive. This regime could become accessible for interesting imaging applications as the beam width of the AC signal of the transmitted light decreases with an increasing frequency. 相似文献
376.
Govind Menon 《Journal of Dynamics and Differential Equations》2016,28(3-4):1031-1038
Let G be the Green’s function for the Airy operator We show that the integral operator defined by G is Hilbert–Schmidt and that the 2-modified Fredholm determinant
相似文献
$$\begin{aligned} L\varphi := -\varphi ''+ x \varphi , \quad 0< x < \infty , \quad \varphi (0)=0. \end{aligned}$$
$$\begin{aligned} {\mathrm {det}}_2(1+zG) = \frac{{\mathrm {Ai}}(z)}{{\mathrm {Ai}}(0)} , \quad z \in {\mathbb {C}}. \end{aligned}$$
377.
ZnAl2O4:Tb phosphor was prepared by combustion synthesis. ZnAl2O4:Tb exhibits three thermally stimulated luminescence (TSL) peaks around 150, 275 and 350 °C. ZnAl2O4:Tb exhibits optically stimulated luminescence (OSL) when stimulated with 470 nm light.Electron spin resonance (ESR) studies were carried out to identify defect centres responsible for TSL peaks observed in ZnAl2O4:Tb. Two defect centres are identified in irradiated ZnAl2O4:Tb phosphor and these centres are assigned to V and F+ centres. V centre appears to correlate with the 150 °C TSL peak, while F+ centre could not be associated with the observed TSL peaks. 相似文献
378.
We report experiments on the equipartition of kinetic energy in a mixture of pairs of different types of grains vibrated in two dimensions. In general, the two types of grains do not attain the same granular temperature, T(g) = 1/2m. However, the temperature ratio is constant in the bulk of the system and independent of the vibration velocity. The ratio depends strongly on the ratio of mass densities of the grains, but not on their inelasticity. Also, the temperature ratio is insensitive to compositional variables such as the number fraction of each component and the total number density. We conclude that a single granular temperature, as traditionally defined, does not characterize a multicomponent mixture. 相似文献
379.
380.
J R Kumar N S Ranadive I A Menon H F Haberman 《Journal of photochemistry and photobiology. B, Biology》1992,14(1-2):125-137
Our studies describe the inflammatory response in rabbit skin induced by topical application of 8-methoxypsoralen (8-MOP) and UVA-visible irradiation (320-700 nm). Increase in vascular permeability (iVP) and accumulation of polymorphonuclear leucocytes (aPMN) at the test sites were quantitated using 125I-albumin and 51Cr-labelled PMNs respectively. Erythema was graded visually. 8-MOP cream was applied topically and irradiated. The erythemal response, aPMN and iVP at the test sites were quantitated at 6, 24, 48 and 72 h post-irradiation. The iVP and aPMN were maximal at 24 h; the erythemal response was the same at 24-48 h. The responses were dependent on 8-MOP concentration and irradiation dose. Topical application of 200 micrograms 8-MOP cream followed by irradiation for 2 h (9.4 J cm-2) produced 3-7 times iVP, 2-4 times aPMN and intense erythema at the test sites after 24 h. Neither aPMN nor iVP was detected before 6 h and erythemal response was not observable up to 16 h after irradiation. The aPMN and iVP gradually subsided in 72 h, although the erythemal response was still present. The repeated exposure of 8-MOP-treated sites for three consecutive days 24 h apart did not produce appreciable iVP or aPMN at 72 h or 24 h after the last exposure; however, erythema persisted. The 8-MOP-treated sites previously exposed for three consecutive days on reapplication of 8-MOP cream plus irradiation showed significantly less response compared with non-pretreated sites. Our results suggest that the erythemal response is not directly related to either iVP or aPMN. 相似文献