全文获取类型
收费全文 | 82篇 |
免费 | 2篇 |
专业分类
化学工业 | 35篇 |
建筑科学 | 8篇 |
轻工业 | 12篇 |
无线电 | 2篇 |
一般工业技术 | 13篇 |
冶金工业 | 2篇 |
原子能技术 | 4篇 |
自动化技术 | 8篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 8篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 2篇 |
1999年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1975年 | 2篇 |
排序方式: 共有84条查询结果,搜索用时 0 毫秒
1.
This report focuses on research into waveguides prepared by K+-Na+ ion exchange with the help of an electric field, and the subsequent comparison with waveguides prepared by pure thermal ion
exchange. The goals of this work were to determine the characteristics of and to address the technological problems associated
with waveguides prepared in two types of highly pure optical glass: special soda-lime silica GIL49 glass produced from pure
raw materials and commercially prepared borosilicate BK7 glass. An appropriate chemical mixture, KNO3:Ca(NO3)2 in the molar ratio of 41:59, was used as the source of potassium ions. Experiments were conducted at temperatures between
250 and 410°C, and electric field values between 0 and 150 V/mm. The number of modes, depth, profile, and the change in refractive
index (Δn) were measured for samples from each type of glass under various technological conditions. All of these parameters
can be controlled accurately and repeatedly by the electric field. These experiments have also shown that a particular advantage
of these types of pure glass is the low waveguide optical losses (0.1 to 0.2 dB/cm) attainable. 相似文献
2.
3.
In this work we extend the approach used in [6] to perform distributed-memory AFMC model checking. The part of a system held in one computer is modeled as a Kripke structure with border states. Moreover, we use assumptions about the truth of a formula in each state. Each process then repeatedly executes a slight modification of a standard sequential algorithm and exchanges its results with other processes. In the paper we define the AFMC semantics for structures with border states and assumptions, present the distributed algorithm and show the main ideas behind the proof of its correctness. Complexity and experimental results are provided as well. 相似文献
4.
The refractive index increments of linear and branched polyethylene were determined for several solvents and various wavelengths (403, 436, 546, and 633 nm), mainly at 135°C. Differences were observed between values for linear and branched samples. Data obtained in this investigation are compared with the reported ones. 相似文献
5.
Andrea Trnková Kateřina Šancová Martina Zapletalová Jitka Kašparovská Kateřina Dadáková Ludmila Křížová Jan Lochman Sylvie Hadrová Ivana Ihnatová Tomáš Kašparovský 《Journal of dairy science》2018,101(6):5134-5144
The aim of this study was to determine the degradation of dietary isoflavones in rumen fluid under 2 feeding regimens. The experiments were performed in vitro using a rumen fluid buffer system. The rumen fluid was taken from cows fed either a hay diet or a concentrate-rich diet (the diet consisted of 34.6% maize silage, 17.6% haylage, 12.8% alfalfa hay, and 35.0% supplemental mixture on a dry matter basis). As a source of isoflavones, 40% soybean extract (Biomedica, Prague, Czech Republic) at levels of 5, 25, 50, and 75 mg per 40 mL of rumen fluid was used. Samples of soybean extract were incubated in triplicate at 39°C for 0, 3.0, 6.0, 12.0, and 24.0 h in incubation solution. The metabolism of daidzein and genistein was faster under concentrate-rich diet conditions. In general, production of equol started after 3 to 6 h of incubation and reached the highest rate after approximately 12 h of incubation regardless of the type of diet or concentration of extract. In most of the experiments, production of equol continued after 24 h of incubation. Generally, equol production was greater under the hay diet conditions. Furthermore, experiments with higher amounts of added soybean extract revealed possible inhibitory effects of high levels of isoflavones on the rumen microflora. 相似文献
6.
Andrew J. Hartshorn George Prpich Andrew Upton Jitka Macadam Bruce Jefferson Peter Jarvis 《Water and Environment Journal》2015,29(1):16-26
This investigation explores the use of five‐parameter logistic curve fitting in quantifying turbidity robustness and risk scoring in clarification and filtrations stages of several surface water treatment works in the Anglian Water region of the United Kingdom. The approach taken reviews different scoring systems and addresses issues of weighting, averages and variability in robustness performance using turbidity robustness indices (TRIs). It also proposes an area‐based risk scoring profile to assess performance [relative area profile for T90 (RAP90)]. The metrics produced are considered to be a logical and rational way to help prioritise where resources for water treatment operation should be deployed. 相似文献
7.
ABSTRACTThe paper deals with a study of tensile strength and disintegration time of compacts made from silicified microcrystalline celluloses, Prosolv SMCC 90, and Prosolv HD 90, in dependence on compression force, addition of two types of lubricants, and two active ingredients. The lubricants were magnesium stearate and sodium stearyl fumarate in a concentration of 0.5%, the active ingredients being ascorbic acid and acetylsalicylic acid in a concentration of 50%.Prosolv SMCC 90 proved to be better compatible than Prosolv HD 90; the compacts were of higher strength, which was markedly increased with increasing compression force. Prosolv HD 90 was more sensitive to additions of lubricants, and a greater decrease in strength was recorded due to the influence of sodium stearyl fumarate. The effect of lubricants on the strength of compacts in the presence of active ingredients was not identical. The disintegration time of compacts from Prosolv HD 90 without as well as with lubricants was shorter than from Prosolv SMCC 90 and was increasing with increasing compression force. Disintegration time was increased with added lubricants, and it was markedly shortened by addition of active ingredients. Compacts containing ascorbic acid possessed a shorter disintegration time than those containing acetylsalicylic acid, and it was not markedly influenced by the presence of lubricants. 相似文献
8.
Ivan Rehor Jitka Slegerova Jan Kucka Vladimir Proks Vladimira Petrakova Marie‐Pierre Adam François Treussart Stuart Turner Sara Bals Pavel Sacha Miroslav Ledvina Amy M. Wen Nicole F. Steinmetz Petr Cigler 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(6):1106-1115
High pressure high temperature (HPHT) nanodiamonds (NDs) represent extremely promising materials for construction of fluorescent nanoprobes and nanosensors. However, some properties of bare NDs limit their direct use in these applications: they precipitate in biological solutions, only a limited set of bio‐orthogonal conjugation techniques is available and the accessible material is greatly polydisperse in shape. In this work, we encapsulate bright 30‐nm fluorescent nanodiamonds (FNDs) in 10–20‐nm thick translucent (i.e., not altering FND fluorescence) silica shells, yielding monodisperse near‐spherical particles of mean diameter 66 nm. High yield modification of the shells with PEG chains stabilizes the particles in ionic solutions, making them applicable in biological environments. We further modify the opposite ends of PEG chains with fluorescent dyes or vectoring peptide using click chemistry. High conversion of this bio‐orthogonal coupling yielded circa 2000 dye or peptide molecules on a single FND. We demonstrate the superior properties of these particles by in vitro interaction with human prostate cancer cells: while bare nanodiamonds strongly aggregate in the buffer and adsorb onto the cell membrane, the shell encapsulated NDs do not adsorb nonspecifically and they penetrate inside the cells. 相似文献
9.
Miloš Janeček Jakub Čížek Jenő Gubicza Jitka Vrátná 《Journal of Materials Science》2012,47(22):7860-7869
Commercial MgAlZn alloy AZ31 was processed by hot extrusion and equal channel angular pressing (ECAP) known as EX-ECAP. Microstructure and defect structure evolution with strain due to ECAP were investigated by TEM, positron annihilation spectroscopy (PAS), and X-ray diffraction. Significant grain refinement was obtained by EX-ECAP. In the extruded condition relatively low density of dislocations was determined by PAS. Sharp increase of dislocation density occurred during the first two passes of ECAP, followed by the saturation and even a decline manifesting the dynamic recovery at higher strains. XRD line profile analysis confirmed the results of PAS with slightly higher values of dislocation densities in individual conditions. Detailed analysis of contrast factors allows to determine the type of dislocations and to draw conclusions about slip activation and its variations with strain. The influence of microstructure evolution on mechanical properties is discussed. 相似文献
10.
The paper deals with a study of tensile strength and disintegration time of compacts made from silicified microcrystalline celluloses, Prosolv SMCC 90, and Prosolv HD 90, in dependence on compression force, addition of two types of lubricants, and two active ingredients. The lubricants were magnesium stearate and sodium stearyl fumarate in a concentration of 0.5%, the active ingredients being ascorbic acid and acetylsalicylic acid in a concentration of 50%.
Prosolv SMCC 90 proved to be better compatible than Prosolv HD 90; the compacts were of higher strength, which was markedly increased with increasing compression force. Prosolv HD 90 was more sensitive to additions of lubricants, and a greater decrease in strength was recorded due to the influence of sodium stearyl fumarate. The effect of lubricants on the strength of compacts in the presence of active ingredients was not identical. The disintegration time of compacts from Prosolv HD 90 without as well as with lubricants was shorter than from Prosolv SMCC 90 and was increasing with increasing compression force. Disintegration time was increased with added lubricants, and it was markedly shortened by addition of active ingredients. Compacts containing ascorbic acid possessed a shorter disintegration time than those containing acetylsalicylic acid, and it was not markedly influenced by the presence of lubricants. 相似文献
Prosolv SMCC 90 proved to be better compatible than Prosolv HD 90; the compacts were of higher strength, which was markedly increased with increasing compression force. Prosolv HD 90 was more sensitive to additions of lubricants, and a greater decrease in strength was recorded due to the influence of sodium stearyl fumarate. The effect of lubricants on the strength of compacts in the presence of active ingredients was not identical. The disintegration time of compacts from Prosolv HD 90 without as well as with lubricants was shorter than from Prosolv SMCC 90 and was increasing with increasing compression force. Disintegration time was increased with added lubricants, and it was markedly shortened by addition of active ingredients. Compacts containing ascorbic acid possessed a shorter disintegration time than those containing acetylsalicylic acid, and it was not markedly influenced by the presence of lubricants. 相似文献