全文获取类型
收费全文 | 456篇 |
免费 | 15篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 130篇 |
金属工艺 | 5篇 |
机械仪表 | 7篇 |
建筑科学 | 47篇 |
矿业工程 | 6篇 |
能源动力 | 4篇 |
轻工业 | 47篇 |
水利工程 | 5篇 |
石油天然气 | 4篇 |
无线电 | 23篇 |
一般工业技术 | 50篇 |
冶金工业 | 67篇 |
原子能技术 | 1篇 |
自动化技术 | 67篇 |
出版年
2023年 | 2篇 |
2022年 | 27篇 |
2021年 | 24篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 27篇 |
2012年 | 24篇 |
2011年 | 41篇 |
2010年 | 19篇 |
2009年 | 16篇 |
2008年 | 38篇 |
2007年 | 27篇 |
2006年 | 16篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1958年 | 3篇 |
1957年 | 2篇 |
排序方式: 共有471条查询结果,搜索用时 15 毫秒
61.
Nataliya A. Mishchuk Trond Heldal Tormod Volden Janko Auerswald Helmut Knapp 《Microfluidics and nanofluidics》2011,11(6):675-684
A micropump based on strong polarization of ion-exchange beads and corresponding actuation by electroosmosis of the second
kind was designed and fabricated. Experimental results from operation with AC and DC voltage showed a close to second order
relationship between flow and voltage, in good agreement with theory. The difference between experimental and theoretical
flow rates and pressures is attributed to the hydrodynamic resistance of the channel network. A modified pump design which
should yield higher flow rates and pressures was suggested. 相似文献
62.
Christian Rosenkilde Liv Hilde Arnesen Oddmund Wallevik 《Journal of Phase Equilibria and Diffusion》2004,25(3):255-258
The solubilities of chloride (Cl) in liquid magnesium (Mg) have been determined from the analysis of quenched samples of liquid
Mg equilibrated with NaCl-MgCl2 melts of different compositions at temperatures in the range 650–790 °C. As an example, the solubility of Cl in liquid Mg
in contact with pure MgCl2 at 735 °C was found to be approximately 18 ppm. The Cl solubility was found to be proportional to the square root of the
MgCl2 activity in the NaCl-MgCl2 melt, indicating that MgCl2 dissolved according to the reaction 0.5MgCl2 + 0.5Mg(l) = MgCl (in Mg). The temperature dependency of the solubility also was measured. Thermodynamic values related to
the dissolution of MgCl2 in liquid Mg have been estimated. 相似文献
63.
A new micromechanics damage model is proposed by averaging distributed microcracks with cohesive zones in a two dimensional representative volume element. The cohesive microcracks are mode-III Dugdale-Bilby-Cottrell-Swinden (Dugdale-BCS) crack. The damage model may be used to construct plasticity potentials that take into account the presence of such microcracks. 相似文献
64.
In 2 experiments, the authors compare stimulus-based versus task-rule-based task performance. Participants practiced 8 stimulus-response mappings either with or without knowledge about 2 underlying task sets. After practice, 2 transfer blocks with 8 new stimuli were presented. Results show that rule knowledge leads to significant switch and transfer costs, whereas without rule knowledge neither switch nor transfer costs occur. However, significant Task Type × Response Type interactions occurred in both conditions. In a second experiment including only the no rule condition, half of the stimulus-response mappings in the transfer blocks were incongruent to the underlying task rule. Slower response times for these incongruent stimuli as compared with congruent stimuli and the absence of switch costs suggest that participants acquired (presumably implicit) knowledge about 4 different stimulus-response categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
One way of adapting and reusing vacant office buildings is conversion into housing. Former research has shown possibilities for this type of conversion, and has delivered instruments for determining the conversion potential of vacant offices. Although adaptation and renovation of outdated offices can prove to be a successful property (real estate) strategy, conversions into housing still only occur on a small scale. There are several reasons for this, including uncertainty about financial feasibility and little knowledge about the opportunities and risks of building conversions. A meta-study of the conversion of 15 office buildings into housing in the Netherlands is used to reveal the drivers for office-to-housing conversions as well as the opportunities and risks that arise in the conversion process. The findings show that various legal, financial, technical, functional and architectonic issues define the opportunities and risks of building conversions. These insights can be used to support the decision-making processes for dealing with vacant office buildings in order to minimize the risks and increase the opportunities. 相似文献
66.
Seung‐Kyun Kang Suk‐Won Hwang Sooyoun Yu Jung‐Hun Seo Elise A. Corbin Jiho Shin Dae Seung Wie Rashid Bashir Zhenqiang Ma John A. Rogers 《Advanced functional materials》2015,25(12):1789-1797
Biodegradable substrates and encapsulating materials play critical roles in the development of an emerging class of semiconductor technology, generally referred as “transient electronics”, whose key characteristic is an ability to dissolve completely, in a controlled manner, upon immersion in ground water or biofluids. The results presented here introduce the use of thin foils of Mo, Fe, W, or Zn as biodegradable substrates and silicate spin‐on‐glass (SOG) materials as insulating and encapsulating layers, with demonstrations of transient active (diode and transistor) and passive (capacitor and inductor) electronic components. Complete measurements of electrical characteristics demonstrate that the device performance can reach levels comparable to those possible with conventional, nontransient materials. Dissolution kinetics of the foils and cytotoxicity tests of the SOG yield information relevant to use in transient electronics for temporary biomedical implants, resorbable environmental monitors, and reduced waste consumer electronics. 相似文献
67.
The potential of night cooling, a passive cooling technique of growing interest, is typically investigated by numerical means. In particular multi-zone energy simulation is currently appraised for building design. Unfortunately, in addition to the inaccurate approximation of an ideally mixed room, the implemented empirical convective heat transfer coefficients (CHTCs) only apply to specific flow regimes - forcing to use arbitrary correlations and, thus, possibly limiting the usefulness of the simulation results. Therefore, the authors of this paper investigate the sensitivity of the night cooling performance to convection algorithms. First, the authors examine the applicability of convection correlations for real building enclosures, extracted from literature. Subsequently, simulations of a night cooled office room during summertime of a moderate climate (Belgium) are carried out in TRNSYS, using different convection correlations in addition to varying design parameters. The results show that the choice of the convection algorithm strongly affects the energy and thermal comfort predictions. More importantly, the convection algorithm is of the same importance as the design parameters - making an exact definition of the CHTC crucial. Therefore, additional research by experiments or airflow codes, based on fluid dynamics, is regarded necessary. 相似文献
68.
Development and application of new nucleic acid-based technologies for microbial community analyses in foods 总被引:8,自引:0,他引:8
Rudi K Nogva HK Moen B Nissen H Bredholt S Møretrø T Naterstad K Holck A 《International journal of food microbiology》2002,78(1-2):171-180
Several challenges still persist in the analysis of microorganisms in foods, particularly in studies of complex communities. Nucleic acid-based methods are promising tools in addressing new questions concerning microbial communities. We have developed several new methods in the field of nucleic acid-based microbial community analyses. These methods cover both sample preparation and detection approaches. The sample preparation method involves simplified DNA purification using paramagnetic beads. As an extension of this method, the same paramagnetic beads are used for both cell separation and DNA purification. This enables full automation. The separate detection of viable and dead bacteria is a major issue in nucleic acid-based diagnostics. We have applied a living/dead dye that binds covalently to DNA and inhibits the PCR from dead cells. In addition, a DNA array-based detection assay has been developed. The assay combines the specificity obtained by enzymatic labeling of DNA probes with the possibility of detecting several targets simultaneously by DNA array hybridization. In combination with 16S rDNA amplification, this is a promising tool for community analyses. Also, we have developed a novel approach for multiplex quantitative PCR. The multiplex PCR has been combined with our DNA array-based detection method. Finally, we are now in the process of adapting a system for monitoring microbial growth and death in real-time through the tagging of bacteria with green fluorescent protein (GFP) combined with fluorescence detection using a high-resolution confocal laser scanner. 相似文献
69.
Hilde Grove Hendrik W. Brinks Ole M. Lvvik Richard H. Heyn Bjrn C. Hauback 《Journal of Alloys and Compounds》2008,460(1-2):64-68
LiMgAlH6 is the intermediate phase when LiMg(AlH4)3 is heated. It contains 9.4 wt.% hydrogen, of which 4.8 wt.% is released during the decomposition step to MgH2 and LiH. Deuterated LiMgAlD6 was prepared by heat-treating LiMg(AlD4)3 at 130 °C. Powder neutron and synchrotron X-ray diffraction patterns were measured and the structure was refined using the Rietveld technique on both patterns simultaneously. LiMgAlD6 crystallizes in the trigonal space group P321 with a = 7.9856(4) Å and c = 4.3789(3) Å. The structure consists of isolated AlD6 octahedra connected through octahedrally coordinated Mg- and Li-atoms. 相似文献
70.
The benefit of nonpharmacological interventions for insomnia in old age was investigated. A total of 13 single-outcome studies from 1966–1998 involving 388 patients (mean age exceeding 60 years, minimum age in sample, 50 years) were included in a meta-analysis of treatment efficacy. This analysis demonstrated that behavioral interventions produce improvements in sleep parameters of older insomniacs, measured in terms of sleep-onset latency, number of nocturnal awakenings, time awake after sleep onset, and total sleep time. Clinical improvements seen at posttreatment were maintained at followups (averaging 6 months). It is concluded that behavioral treatments produce significant and long-lasting improvements in the sleep pattern of older insomniacs. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献