全文获取类型
收费全文 | 1472篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
化学 | 1000篇 |
力学 | 8篇 |
数学 | 2篇 |
物理学 | 464篇 |
出版年
2019年 | 1篇 |
2015年 | 1篇 |
2013年 | 1篇 |
2012年 | 122篇 |
2011年 | 163篇 |
2010年 | 22篇 |
2009年 | 4篇 |
2008年 | 143篇 |
2007年 | 155篇 |
2006年 | 165篇 |
2005年 | 143篇 |
2004年 | 138篇 |
2003年 | 94篇 |
2002年 | 63篇 |
2001年 | 49篇 |
2000年 | 47篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 3篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 18篇 |
1992年 | 18篇 |
1991年 | 7篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1948年 | 5篇 |
排序方式: 共有1474条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
A method has been developed for the determination of gaseous nitric acid in air based on its separation from particulate nitrate aerosol using diffusion denuder tubes. An integrated value of nitric acid concentration in air is obtained. The experimentally derived absorption efficiencies of the diffusion denuder tubes ranged from 87.6 to 96.9%. The standard deviation of the method was calculated as 0.10 mug/m(3) for nitric acid concentrations in the range 0.54-1.72 mug/m(3). A correction procedure, using two diffusion denuders in series, should be applied if measurements are made in the presence of high levels of nitrogen oxides. 相似文献
7.
An electrolytic device for decomposition of water has been developed which readily gives hydrogen and oxygen for isotopic measurement with a mass spectrometer. A 20-mul sample can be decomposed quantitatively in 10 min with good reproducibility. The results produced are comparable with those obtained by reduction with uranium. 相似文献
8.
9.
10.
Eldefrawi ME Azer NL Nath N Anis NA Bangalore MS O'Connell KP Schwartz RP Wright J 《Applied biochemistry and biotechnology》2000,87(1):25-35
An automated flow fluorometer designed for kinetic binding analysis was adapted to develop a solid-phase competitive fluoroimmunoassay
for urinalysis of opiates. The solid phase consisted of polymer beads coated with commercial monoclonal antibodies (MAbs)
raised against morphine. Fluorescein-conjugated morphine (FL-MOR) was used as the fluorescein-labeled hapten. The dissociation
equilibrium constant (K
D
) for the binding of FL-MOR to the anti-MOR MAb was 0.23 nM. The binding of FL-MOR to the anti-MOR MAb reached steady state within minutes and was displaced effectively by morphine
and other opiates. Morphine-3-glucuronide (M3G), the major urinary metabolite of heroin and morphine, competed effectively
with FL-MOR in a concentration-dependent manner for binding to the antimorphine MAb and was therefore used to construct the
calibration curve. The sensitivity of the assay was 0.2 ng/mL for M3G. The assay was effective at concentrations of M3G from
0.2 to 50 ng/mL, with an IC50 of 2 ng/mL. Other opiates and heroin metabolites that showed >50% crossreactivity when present at 1 μg/mL included codeine,
morphine-6-glucuronide, and oxycodone. Methadone showed very low crossreactivity (<5%), which is a benefit for testing in
patients being treated for opiate addictions. The high sensitivity of the assay and the relatively high cutoff value for positive
opiate tests allows very small sample volumes (e.g., in saliva or sweat) to be analyzed. A double-blind comparison using 205
clinical urine samples showed good agreement between this single-step competitive assay and a commercially performed enzyme
multiplied immunoassay technique for the detection of opiates and benzoylecgonine (a metabolite of cocaine). 相似文献