全文获取类型
收费全文 | 1446篇 |
免费 | 39篇 |
专业分类
化学 | 663篇 |
晶体学 | 10篇 |
力学 | 41篇 |
数学 | 86篇 |
物理学 | 435篇 |
无线电 | 250篇 |
出版年
2021年 | 16篇 |
2020年 | 18篇 |
2019年 | 15篇 |
2018年 | 10篇 |
2016年 | 20篇 |
2015年 | 18篇 |
2014年 | 23篇 |
2013年 | 57篇 |
2012年 | 46篇 |
2011年 | 58篇 |
2010年 | 41篇 |
2009年 | 37篇 |
2008年 | 61篇 |
2007年 | 75篇 |
2006年 | 71篇 |
2005年 | 55篇 |
2004年 | 59篇 |
2003年 | 38篇 |
2002年 | 37篇 |
2001年 | 39篇 |
2000年 | 32篇 |
1999年 | 16篇 |
1998年 | 15篇 |
1997年 | 25篇 |
1996年 | 22篇 |
1995年 | 29篇 |
1994年 | 34篇 |
1993年 | 42篇 |
1992年 | 21篇 |
1991年 | 14篇 |
1990年 | 22篇 |
1989年 | 22篇 |
1988年 | 18篇 |
1987年 | 11篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 23篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 27篇 |
1977年 | 16篇 |
1976年 | 28篇 |
1975年 | 17篇 |
1974年 | 24篇 |
1973年 | 14篇 |
1972年 | 18篇 |
1970年 | 9篇 |
排序方式: 共有1485条查询结果,搜索用时 78 毫秒
51.
52.
53.
54.
55.
Summary In the determination of several perhalogenated compounds after gas chromatographic separation on an Apiezon L column, using
a flame ionization detector, all the compounds tested gave linear area-mass plots although the coefficients observed do not
lead to extrapolations which would permit quantitation of perhalogenated compounds for which no standard is available. Of
the compounds tested, dibromodichloromethane, tetrachloroethene and tetrabromoethene gave good linear correlations of area
ratio-mass ratio (using n-decane as the internal standard). Bromotrichloromethane and tetrabromomethane gave continuously
curving area ratio-mass ratio plots which were very reproducible and could be used for graphical interpolation. 相似文献
56.
A History of Fischer-Tropsch Wax Upgrading at BP—— from Catalyst Screening Studies to Full Scale Demonstration in Alaska
下载免费PDF全文
![点击此处可从《天然气化学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
John P. Collins Joep J. H. M. Font Freidet Barry Nay 《天然气化学杂志》2006,15(1):1-10
Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability (catalyst life) were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics. 相似文献
57.
58.
W. Harvey Newsome Peter Collins 《International journal of environmental analytical chemistry》2013,93(4):489-494
Abstract A method was developed for the determination of three fungicides in foods based on alkaline degradation to 3,5-dichloroaniline, isolation of the latter by steam distillation and measurement of the heptafluorobutyrate by gas chromatography. Recoveries averaged 91% from several commodities spiked at from 10–80ppb. The minimum detectable limit of 2.6ppb was attainable in grape, with similar limits found in strawberry, tomato and beans. The method was capable of determining degradation products formed as a result of cooking. 相似文献
59.
60.