全文获取类型
收费全文 | 2169篇 |
免费 | 127篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 31篇 |
综合类 | 8篇 |
化学工业 | 641篇 |
金属工艺 | 40篇 |
机械仪表 | 45篇 |
建筑科学 | 117篇 |
矿业工程 | 6篇 |
能源动力 | 69篇 |
轻工业 | 198篇 |
水利工程 | 20篇 |
石油天然气 | 7篇 |
无线电 | 182篇 |
一般工业技术 | 389篇 |
冶金工业 | 170篇 |
原子能技术 | 20篇 |
自动化技术 | 358篇 |
出版年
2023年 | 27篇 |
2022年 | 26篇 |
2021年 | 44篇 |
2020年 | 35篇 |
2019年 | 46篇 |
2018年 | 52篇 |
2017年 | 52篇 |
2016年 | 72篇 |
2015年 | 67篇 |
2014年 | 83篇 |
2013年 | 117篇 |
2012年 | 102篇 |
2011年 | 145篇 |
2010年 | 106篇 |
2009年 | 96篇 |
2008年 | 113篇 |
2007年 | 101篇 |
2006年 | 78篇 |
2005年 | 82篇 |
2004年 | 58篇 |
2003年 | 68篇 |
2002年 | 50篇 |
2001年 | 37篇 |
2000年 | 36篇 |
1999年 | 38篇 |
1998年 | 60篇 |
1997年 | 37篇 |
1996年 | 36篇 |
1995年 | 34篇 |
1994年 | 28篇 |
1993年 | 31篇 |
1992年 | 18篇 |
1991年 | 22篇 |
1990年 | 22篇 |
1989年 | 20篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 20篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 17篇 |
1977年 | 9篇 |
1976年 | 17篇 |
1974年 | 12篇 |
1973年 | 9篇 |
排序方式: 共有2301条查询结果,搜索用时 218 毫秒
911.
912.
Carolin Prechtl Manfred Kraut Matthias Franzreb Gerald Brenner-Weiß Roland Dittmeyer 《化学工程与技术》2017,40(4):670-677
Although microfluidic solvent extraction (µSX) is a recent field in separation, its application is still limited to single‐channel microfluidic devices. However, the industrial application of microheat exchangers has already proven that parallelization of microchannels is an important tool to increase the specific device efficiency. Hence, in this study, a multichannel system for µSX is introduced. As a model process, D,L‐5‐phenylhydantoin was extracted from ethyl acetate into aqueous buffer. By means of different experimental setups, the potential and limitations of membrane‐supported multichannel µSX were investigated. The reactor dimensions perpendicular to flow and transmembrane mass transport are the most challenging factors for the introduced device. 相似文献
913.
914.
915.
916.
Robustified rank tests, applying a robust scale estimator, are investigated for reliable and fast shift detection in time series. The tests show good power for sufficiently large shifts, low false detection rates for Gaussian noise and high robustness against outliers. Wilcoxon scores in combination with a robust and efficient scale estimator achieve good performance in many situations. 相似文献
917.
The concept of steam drying originates from the mid of the last century. However, a broad industrial acceptance of the technique has so far not taken place. The paper deals with modelling the steam drying process and applications of steam drying with in certain industrial sectors where the technique has been deemed to hove special opponunities.
In the modelling scction the mass and heat transfer proceases are described along with equilibrium, capillarity and sorption phenomena occurring in porous materials during the steam drying process. In addition existing models in the literslure are presented.
The applications discussed involve drying of fuels with high moisture contcna, cattle feed exemplified by sugar beet pulp. lumber. paper pulp. paper and sludges.
Steam drying is compared to flue gas drying of biofuels prior to combustion in a boiler. With reference to a current insrallation in Sweden. the exergy losses. as manifested by loss of co-generation cupacity. are discussed. The energy saving potentid when using steam drying of sugar beet pulp as compared to other possible plant configurations is demonstrated.
Mechanical vapour recompression applied to steam drying is analysed with reference to reponed dau from industriul plsnts. Finally. environmcntul advantages when using steam drying are presented. 相似文献
In the modelling scction the mass and heat transfer proceases are described along with equilibrium, capillarity and sorption phenomena occurring in porous materials during the steam drying process. In addition existing models in the literslure are presented.
The applications discussed involve drying of fuels with high moisture contcna, cattle feed exemplified by sugar beet pulp. lumber. paper pulp. paper and sludges.
Steam drying is compared to flue gas drying of biofuels prior to combustion in a boiler. With reference to a current insrallation in Sweden. the exergy losses. as manifested by loss of co-generation cupacity. are discussed. The energy saving potentid when using steam drying of sugar beet pulp as compared to other possible plant configurations is demonstrated.
Mechanical vapour recompression applied to steam drying is analysed with reference to reponed dau from industriul plsnts. Finally. environmcntul advantages when using steam drying are presented. 相似文献
918.
This placebo-controlled, double-blind, double-dummy, independent groups study directly compared effects of the benzodiazepine, lorazepam (2.0 mg/70 kg orally administered), and the anticholinergic scopolamine (0.6 mg/70 kg subcutaneously administered) on memory and attentional measures hypothesized to differentiate the drugs. At the studied doses, lorazepam and scopolamine produced similar decrements in psychomotor performance, free recall, and overall sensitivity in distinguishing between studied and nonstudied items on a recognition memory test. However, the drugs differed with respect to effects on working memory, response bias, metacognition, subjective awareness, and selective attention. In addition to providing information about the cognitive psychopharmacological profiles of drugs with distinct neurochemical and pharmacological mechanisms of action, this study also informs the understanding of memory and attentional processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
919.
Griffiths Roland R.; Rush Craig R.; Puhala Kimberly A. 《Canadian Metallurgical Quarterly》1996,4(1):97
Three experiments demonstrated the validity of studying drug reinforcement in humans by using a novel Multiple-Choice Procedure. The distinguishing characteristic of the procedure is that it arranges intermittent reinforcement for choices between pairs of potential reinforcers (e.g., drug vs. money). A series of manipulations was conducted. the outcomes of which were predicted on the basis of a well-established literature on operant behavior maintained by food and drug. Specifically, the experiments manipulated reinforcer availability (i.e., extinction), deprivation versus satiation, and reinforcer magnitude in cigarette smokers and demonstrated the predicted changes in cigarette reinforcement as measured by the Multiple-Choice Procedure. Finally, the reinforcer magnitude manipulation was concurrently studied using a conventional two-option choice procedure and the results were shown to be virtually identical to those with the Multiple-Choice Procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
920.
Roland G Rotter Ronald R Marquardt Andrzej A Frohlich David Abramson 《Journal of the science of food and agriculture》1990,50(2):155-166
The feasibility of ensiling barley contaminated with ochratoxin A (OA) as a practical method of inactivating OA was examined in in-vitro and in-vivo studies. In the in-vitro study, OA concentrations in barley decreased by approximately 68% after being ensiled for 56 days. To verify the destruction of the OA, a chick feeding trial was conducted. Samples of a toxin-and mould-free barley, mould-contaminated barley, a barley sample naturally contaminated with OA or a barley with added OA were each divided into two equal portions, one of which was ensiled for a period of 28 days. The mould-contaminated barley was naturally contaminated with Penicillium cyclopium and Aspergillus flavus. Diets containing either the ensiled or non-ensiled barley samples were then fed to 7-day-old Leghorn chicks for two 7-day periods. Changes in feed consumption (RFC) and body weight gain (RWG) relative to control birds, feed to gain ratio and mortality were monitored. The OA concentration in the two OA-containing barley samples decreased by 58% after 28 days of ensiling, but there was no improvement (P >0.05) in chick performance or mortality compared with the non-ensiled diets. The average RFC values for chicks fed the mould- and OA-containing diets were less than 50% of the controls and RWG generally less than 30%. In absolute terms, chicks fed the ensiled barley diets also performed about 6% poorer (P <0.003) than those given the non-ensiled barley. Ensiling did not appear to be a practical method of reducing teh toxic effect(s) of OA, despite the apparent decrease in OA concentration. Grain sampkles should be tested for the presence of a toxin prior to ensiling to avoid possible toxin analysis problems later. 相似文献