全文获取类型
收费全文 | 163篇 |
免费 | 1篇 |
专业分类
化学 | 135篇 |
力学 | 2篇 |
数学 | 3篇 |
物理学 | 24篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2016年 | 2篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 15篇 |
2007年 | 5篇 |
2006年 | 13篇 |
2005年 | 7篇 |
2004年 | 14篇 |
2003年 | 5篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 0 毫秒
161.
K. Watanabe H. Hattori M. Nishikawa A. Ishii T. Kumazawa H. Seno O. Suzuki 《Chromatographia》1997,44(1-2):55-58
Summary Cocaethylene together with cocaine spiked in human whole blood has been found measurable at high sensitivities by capillary
gas chromatography with surface ionization detection. The drugs could be rapidly extracted by Sep-Pak C18 cartridges with recovery of more than 60%. The calibration curves for both cocaethylene and cocaine using cocapropylene as
internal standard were linear in the range 50–300 pmol mL−1 of whole blood. The detection limits of cocaethylene and cocaine were 5–10 pmol mL−1 (0.1–0.2 pmol on column if recovery is 100%). Cocaethylene could be determined for whole blood obtained from rats (ca. 200
g body wt.), which had received subcutaneous injection of 10 mg cocaine hydrochloride and 2.0 mL of 30% (v/v) ethanol 3 h
before sampling; the mean levels of cocaethylene and cocaine were 101 and 1230 pmol mL−1, respectively. 相似文献
162.
Tsuneyuki Sato Sumio Shimooka Makiko Seno Hitoshi Tanaka 《Journal of polymer science. Part A, Polymer chemistry》1995,33(17):2865-2873
The radical polymerization behavior of ethyl ortho-formyl-phenyl fumarate (EFPF) using dimethyl 2,2′-azobisisobutyrate (MAIB) as initiator was studied in benzene kinetically and ESR spectroscopically. The polymerization rate (Rp) at 60°C was given by Rp = k[MAIB]0.76[EFPF]0.56. The number-average molecular weight of poly(EFPF) was in the range of 1600–2900. EFPF was also easily photopolymerized at room temperature without any photosensitizer probably because of the photosensitivity of the formyl group of monomer. Analysis of 1H? and 13C-NMR spectra of the resulting polymer revealed that the radical polymerization of EFPF proceeds in a complicated manner involving vinyl addition and intramolecular hydrogen-abstraction. The polymerization system was found to involve ESR-observable poly(EFPF) radicals under the actual polymerization conditions. ESR-determined rate constant (2.4–4.0 L/mol s) of propagation at 60°C increased with decreasing monomer concentration, which is mainly responsible for the observed low de-pendency of Rp on the EFPF concentration. Copolymerizations of EFPF with some vinyl monomers were also examined. © 1995 John Wiley & Sons, Inc. 相似文献
163.
The polymerization of di-2[2-(2-methoxyethoxy)ethoxy]ethyl itaconate (1) with dimethyl 2,2-azobisisobutyrate (2) was studied, in benzene, kinetically and spectroscopically with the electron paramagnetic resonance (EPR) method. The polymerization rate (R
p) at 50°C is given by the equation:R
p=k[2]0.48 [1]2.4. The overall activation energy of polymerization was calculated to be 34 kJ·mol–1. From an EPR study, the polymerization system was found to involve EPR-observable propagating polymer radicals of 1 under the actual polymerization conditions. Using the polymer radical concentration, the rate constants of propagation (k
p) and termination (k
t) were determined. With increasing monomer concentration,k
p(1.54.3 L·mol–1·s–1 at 50°C) increases andk
t
(1.0·1044.2·104 L·mol–1·s–1 at 50°C) decreases, which seems responsible for the high dependence ofR
p on the monomer concentration. The activation energies of propagation and termination were calculated to be 11 kJ·mol–1 and 84 kJ·mol–1, respectively. For the copolymerization of 1(M
1) and styrene (M
2) at 50°C in benzene the following copolymerization parameters were found:r
1=0.2,r
2=0.53, Q1=0.57, ande
1=+0.7. 相似文献
164.
We study the unzipping of double stranded DNA by applying a pulling force at a fraction s (0< or =s < or =1) from the anchored end. From exact analytical and numerical results, the complete phase diagram is presented. The phase diagram shows a strong ensemble dependence for various values of s. In addition, we show the existence of an eye phase and a triple point. 相似文献