全文获取类型
收费全文 | 352篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 150篇 |
晶体学 | 1篇 |
力学 | 64篇 |
数学 | 23篇 |
物理学 | 119篇 |
出版年
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2014年 | 14篇 |
2013年 | 8篇 |
2012年 | 19篇 |
2011年 | 17篇 |
2010年 | 11篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 16篇 |
2006年 | 5篇 |
2005年 | 9篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 3篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1973年 | 9篇 |
1972年 | 3篇 |
1969年 | 2篇 |
1966年 | 2篇 |
1944年 | 2篇 |
1931年 | 2篇 |
1928年 | 4篇 |
1881年 | 2篇 |
1870年 | 2篇 |
排序方式: 共有357条查询结果,搜索用时 0 毫秒
51.
52.
A cobalt porphyrin equipped with two different but geometrically complementary pyridine ligands self-assembles to form an unusually stable complex with approximately 12 porphyrin monomers arranged in a macrocyclic array. 相似文献
53.
Single shot spatially and spectrally resolved laser induced predissociation fluorescence measurements in a shock layer around a cylinder in a pulsed supersonic free stream are presented. Fluoresence signals were produced using the tuned output of an argon fluoride excimer laser to excite a mixture of rovibrational transitions in molecular oxygen. The signals produced along a line inside the shock layer were focussed onto a two dimensional detector coupled to a spectrometer, thus allowing spectral and spatial resolution of the fluoresence. In this way, it was possible to detect two fluoresence signals from two different transitions simultaneously, allowing the determination of vibrational temperatures without the need for calibration. To minimize problems associated with low signal to noise ratios, background subtraction and spatial averaging was required.This article was processed using Springer-Verlag TEX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society. 相似文献
54.
C.M. Sutton 《Solid State Communications》1975,16(3):327-330
The optical properties of amorphous Mg-Bi alloys have been studied in the near infrared and visible spectral regions. Amorphous Mg3Bi2 is found to be a semiconductor with a band gap of 0.152 ± 0.005 eV. Excess Mg or Bi in amorphous Mg3 Bi2 is shown to form localised states near the Fermi level which fill in the pseudogap. These results are inconsistent with the rigid band model proposed by Ferrier and Herrell. 相似文献
55.
An in situ caged crayfish experiment was conducted in the Wabigoon River System, Ontario, Canada to determine the relative importance of food and water pathways for mercury accumulation in crayfish. Two groups of 160 crayfish were suspended in the water column; one at an ucontaminated site, the other at a location with highly elevated total mercury and methylmercury levels in water. Crayfish at each site were divided into two groups. Crayfish were fed either sucker flesh obtained from an uncontaminated lake (low mercury diet) or walleye flesh from contaminated Clay Lake, Ontario, Canada (high mercury diet). After 10 weeks crayfish at both sites fed the high mercury diet had over 20 times mercury accumulation compared to crayfish on the low mercury diet. There was no statistical effects due to sharply elevated water concentrations of total and methylmercury on mercury bodyburdens. This indicated that food was the dominant pathway for mercury accumulation in crayfish. 相似文献
56.
57.
R. S. Adrain D. J. Brassington S. Sutton R. H. Varey 《Optical and Quantum Electronics》1979,11(3):253-264
The use of differential lidar for measuring SO2 in plumes from fossil fuelled power stations is examined. The potential of the technique is investigated for the measurement of SO2 close to power station stacks and in situations where the long range transport of emissions is important. Detection limits are discussed as a function of range and spatial resolution and it is shown theoretically that concentrations as low as 10 ppb at a range of 2 km should be measurable. Details of a prototype, computer controlled, differential lidar based on a tunable dye laser are given and its mode of operation described. Results from field experiments carried out at Drax power station in Yorkshire (UK) and Fawley Power Station in Hampshire (UK) are presented. For plumes of small diameter a deconvolution technique has been applied to obtain better spatial resolution of the plume structure. 相似文献
58.
G. J. Sutton B. J. Tighe 《Journal of polymer science. Part A, Polymer chemistry》1973,11(5):1069-1077
The various types of polyester degradation known to occur at elevated temperature are briefly summarized with particular reference to features of potential diagnostic value. Although little is known of poly-α-ester degradation in particular, examination of work on other linear polyesters indicates the spectrum of analytical and kinetic information that will be needed to characterize the degradation of poly-α-esters of various structures. On the basis of this review, an apparatus has been designed which enables kinetic information to be simultaneously obtained by thermogravimetry, gas evolution analysis, and rheological studies of the residual polymer melt. In addition a gas sampling procedure enables twin-column gas-liquid chromatographic analysis to be carried out on the degradation products. Samples of the chromatographically separated degradation products are collected in a microcollector cell for infrared and mass spectrometric analysis. Other refinements include in-line filament and Curie-point pyrolysis techniques. 相似文献
59.
William A. Page Ralph E. Sutton Robert J. Miller 《Journal of Quantitative Spectroscopy & Radiative Transfer》1973,13(12):1343-1364
A computer program is developed which predicts the vertical distribution of an absorbing species in an isotropically-scattering, finite planetary atmosphere from measurements of the upwelling band radiance determined by a vertically traversing 2-channel radiometer. Comparison is made with experiment. 相似文献
60.