全文获取类型
收费全文 | 483篇 |
免费 | 73篇 |
国内免费 | 22篇 |
出版年
2024年 | 5篇 |
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 19篇 |
2019年 | 16篇 |
2018年 | 16篇 |
2017年 | 28篇 |
2016年 | 24篇 |
2015年 | 12篇 |
2014年 | 23篇 |
2013年 | 39篇 |
2012年 | 10篇 |
2011年 | 31篇 |
2010年 | 11篇 |
2009年 | 16篇 |
2008年 | 35篇 |
2007年 | 28篇 |
2006年 | 24篇 |
2005年 | 21篇 |
2004年 | 18篇 |
2003年 | 11篇 |
2002年 | 17篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 16篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有578条查询结果,搜索用时 31 毫秒
131.
A new sensitive electrochemical sensor, a glassy carbon electrode modified with chemically cross-linked copper-complexed chitosan/multiwalled carbon nanotubes (Cu–CS/MWCNT/GCE), for rutin analysis was constructed. Experimental investigations of the influence of several parameters showed that the rutin can effectively accumulate on the surface of the Cu–CS/MWCNT/GCE, which accumulation caused a pair of well-defined redox peaks in the electrochemical signal when measurements were carried out in Britton–Robinson buffer solution (pH 3, 0.04 M). The surface of the Cu–CS/MWCNT/GCE was characterized by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry analysis. In a rutin concentration range of 0.05–100 μM and under optimized conditions, a linear relationship between the oxidation peak current of rutin and its concentration was obtained with a detection limit of 0.01 μM. The Cu–CS/MWCNT/GCE showed good selectivity, stability, and reproducibility. Moreover, the sensor was used to determine the presence of rutin in fruits with satisfactory results. 相似文献
132.
Enhanced Efficiency and Stability of Perovskite Solar Cells Through Nd‐Doping of Mesostructured TiO2
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bart Roose Karl C. Gödel Sandeep Pathak Aditya Sadhanala Juan Pablo Correa Baena Bodo D. Wilts Henry J. Snaith Ulrich Wiesner Michael Grätzel Ullrich Steiner Antonio Abate 《Liver Transplantation》2016,6(2)
Block‐copolymer templated chemical solution deposition is used to prepare mesoporous Nd‐doped TiO2 electrodes for perovskite‐based solar cells. X‐ray diffraction and photothermal deflection spectroscopy show substitutional incorporation into the TiO2 crystal lattice for low Nd concentration, and increasing interstitial doping for higher concentrations. Substitutional Nd‐doping leads to an increase in stability and performance of perovskite solar cells by eliminating defects and thus increasing electron transport and reducing charge recombination in the mesoporous TiO2. The optimized doping concentration of 0.3% Nd enables the preparation of perovskite solar cells with stabilized power conversion efficiency of >18%. 相似文献
133.
134.
The type and number of respiratory chain components present in membranes of Thiobacillus ferrooxidans have been investigated. These redox components were resolved potentiometrically and kinetically. Using optical techniques two cytochromes a1, multiple cytochromes c and two cytochromes b were detected. By using electron paramagnetic resonance, two copper-containing centres, high and low spin ferric haems and a ferredoxin centre were detected. Based on the combination of a potentiometric resolution and a kinetic study a model for the sequence of the respiratory chain components in the Fe2+ to O2 branch of the T. ferrooxidans respiratory chain is proposed. 相似文献
135.
A method of cyclic voltammetry was used for the determination of cysteine in rat organs in vivo after its intravenous injection. The cyclic polarization enabled a periodic reactivation of the platinum test electrode surface so that reproducible results could be obtained. The peaks of the I-E curve which were due to oxidation of cysteine depended for reproducibility on the concentration of cysteine injected. We attempted to use the method described for the assessment of kidney tissue blood supply before transplantation. 相似文献
136.
Electrochemical regeneration of NAD was performed in a bench scale reactor in which yeast alcohol dehydrogenase catalyzed the oxidation of ethanol. By recycling one of the products of the reaction, it was possible to displace the equilibrium and favor the production of acetaldehyde. The flow-through electrode was made of graphite felt and had a specific area of 275 cm(-1). A mathematical model taking into account the enzymatic and electrochemical reaction rates as well as the mass transfer to the electrode was used to analyze the results. The limiting steps in the reactor are the electrochemical reaction for low potentials and the cofactor mass transfer for high potentials. 相似文献
137.
Microbial electrodes for the determination of ammonia and the estimation of biochemical oxygen demand (BOD) were applied to the nitrogen elimination process. The dimensions of the nitrification and the denitrification vessels were 170 and 70 L, respectively. The wastewater used for the experiment was obtained from a fermentation factory and adjusted to 470-530 mg/L of total Kjeldahl nitrogen and 1700-3000 mg/L of BOD. The ammonia electrode was assembled with a membrane containing nitrifying bacteria and an oxygen probe. The BOD electrode was similarly constructed, except it used a membrane containing the yeast, Trichosporon cutaneum. A flow system was employed for the automatic measurement of samples every 30 min. The nitrification and denitrification rates of the activated sludge were measured to investigate the optimum conditions and evaluate the capacity of the plant. The various data obtained by the microbial electrodes allowed us to inspect the situation of the plant and estimate control paramerers such as nitrogen and BOD loadings. The average removals of ammonia nitrogen and total Kjeldahl nitrogen were 96% and 89%, respectively, during the experiment for period of 2 weeks. 相似文献
138.
Colloidal gold as a biocompatible immobilization matrix suitable for the fabrication of enzyme electrodes by electrodeposition 总被引:11,自引:0,他引:11
Crumbliss AL Perine SC Stonehuerner J Tubergen KR Zhao J Henkens RW O'Daly JP 《Biotechnology and bioengineering》1992,40(4):483-490
Glucose oxidase, horseradish peroxidase, xanthine oxidase, and carbonic anhydrase have been adsorbed to colloidal gold sols with good retention of enzymatic activity. Adsorption of xanthine oxidase on colloidal gold did not result in a change in enzymatic activity as determined by active site titration with the stoichiometric inhibitor pterin aldehyde and by measurement of the apparent Michaelis constant (K'(M)). Gold sols with adsorbed glucose oxidase, horseradish peroxidase, and xanthine oxidase have also been electrodeposited onto conducting matrices (platinum gauze and/or glassy carbon) to make enzyme electrodes. These electrodes retained enzymatic activity and, more importantly, gave an electrochemical response to the enzyme substrate in the presence of an appropriate electron transfer mediator. Our results demonstrate the utility of colloidal gold as a biocompatible enzyme imobilization matrix suitable for the fabrication of enzyme electrodes. (c) 1992 John Wiley & Sons, Inc. 相似文献
139.
This paper is concerned with the definition of the standard conditions required for optimum operation of the bare platinum electrode with photosynthetic samples. Experimental evidence shows the following: 1) Polarization circuits should have zero resistance; 2) The electrolyte layer between the electrodes should have a conductance higher than 54×10–6 –1 per mm2 of platinum electrode area; 3) The electrodes should be polarized just before taking the measurements. All these facts can be interpreted in terms of phenomena occurring on the electrode: The adsorption of hydrogen on the electrode imposes the need for low resistances in the system, and oxygen consumption by the electrode is minimized by polarizing the electrodes as late as possible. This investigation increases the reliability of the bare platinum electrode and gives a basis for a comparison of the results from different experiments. Demonstrations of the pertinence of these conditions are made in our lab with the algae Dunaliella Tertiolecta. 相似文献
140.
Studies on acetylcholine sensor and its analytical application based on the inhibition of cholinesterase 总被引:7,自引:0,他引:7
Acetylcholine esterase electrodes, based on glass, Pd/PdO and Ir/IrO2 electrodes as pH sensor, using the immobilized acetylcholine esterase in acrylamide-methacrylamide hydrazides prepolymer are reported and compared. New data on the analysis of nicotine, fluoride ion, and some organophosphorus compounds are reported using the present AChE sensor based on the inhibition of the immobilized acetylcholine esterase. Reactivation of immobilized AChE after inhibition with reversible inhibitor, i.e. nicotine and fluoride ion is carried out using a mixture of working buffer and acetylcholine, whereas reactivation after inhibition with irreversible inhibitor, i.e. organophosphorus compounds is carried out using a mixture of acetylcholine and pyridine-2-aldoxime methiodide (PAM). The detection limits for the nicotine and fluoride ion are found to be 10−5M whereas for paraoxon, methyl parathion and malathion are found to be 10−9 M and 10−10 M. 相似文献