全文获取类型
收费全文 | 3543篇 |
免费 | 395篇 |
国内免费 | 104篇 |
专业分类
电工技术 | 119篇 |
综合类 | 196篇 |
化学工业 | 1011篇 |
金属工艺 | 28篇 |
机械仪表 | 96篇 |
建筑科学 | 60篇 |
矿业工程 | 160篇 |
能源动力 | 29篇 |
轻工业 | 1314篇 |
水利工程 | 17篇 |
石油天然气 | 115篇 |
武器工业 | 15篇 |
无线电 | 169篇 |
一般工业技术 | 255篇 |
冶金工业 | 182篇 |
原子能技术 | 23篇 |
自动化技术 | 253篇 |
出版年
2024年 | 17篇 |
2023年 | 73篇 |
2022年 | 182篇 |
2021年 | 269篇 |
2020年 | 165篇 |
2019年 | 165篇 |
2018年 | 121篇 |
2017年 | 138篇 |
2016年 | 142篇 |
2015年 | 154篇 |
2014年 | 215篇 |
2013年 | 273篇 |
2012年 | 283篇 |
2011年 | 266篇 |
2010年 | 181篇 |
2009年 | 187篇 |
2008年 | 179篇 |
2007年 | 191篇 |
2006年 | 146篇 |
2005年 | 121篇 |
2004年 | 130篇 |
2003年 | 88篇 |
2002年 | 77篇 |
2001年 | 38篇 |
2000年 | 55篇 |
1999年 | 37篇 |
1998年 | 18篇 |
1997年 | 21篇 |
1996年 | 11篇 |
1995年 | 16篇 |
1994年 | 8篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1964年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有4042条查询结果,搜索用时 31 毫秒
51.
Minimum Setup Minimum Aberration Two‐level Split‐plot Type Designs for Physical Prototype Testing
下载免费PDF全文
![点击此处可从《Quality and Reliability Engineering International》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Linda Lee Ho Carla A. Vivacqua André Luís Santos de Pinho 《Quality and Reliability Engineering International》2016,32(3):1007-1020
Although new technologies allow for less effort in prototyping, physical testing still remains an important step in the product development cycle. Well‐planned experiments are useful to guide the decision‐making process. During the design of an experiment, one of the challenges is to balance limited resources and system constraints to obtain useful information. It is common that prototypes are composed of several parts, with some parts more difficult to assemble than others. And, usually, there is only one piece available of each part type and a large number of different setups. Under these conditions, designs with randomization restrictions become attractive approaches. Considering this scenario, a new and additional criterion, minimum setup, to construct split‐plot type designs is presented. Designs with the minimum number of setups of the more difficult parts, which are especially useful for screening purposes in physical prototype testing, are discussed. The use of the proposed criterion combined with minimum aberration for selecting a regular design is shown through a real application in testing car prototypes. As a tool to practitioners, catalogs of selected 32‐run minimum setup minimum aberration split‐split‐plot and split‐split‐split‐plot designs are presented. More complete catalogs are available as Supporting information. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
52.
目的 以乳制品包装为研究对象,建立一套科学评价食品接触材料安全风险的方法,全面评价食品接触材料在接触食品过程中带来的食品安全风险。方法 采用非靶向高通量筛查检测技术全面筛查食品模拟物中的重金属和有机物,根据权威数据库和物质毒理学资料进行危害评估,参考欧盟和美国膳食暴露量计算方法进行暴露评估,结合评估结果计算风险系数,最终表征食品接触材料的安全风险。结果 抽取了市面上的塑料、金属、涂料及复合包装等不同材质的乳制品包装进行检测,检出铜、铬、锰和锡等元素,以及有意添加物(如单体、溶剂、抗氧剂、光引发剂、爽滑剂、增塑剂等)、非有意添加物质(如抗氧剂降解产物、寡聚物等)。采用暴露评估和危害评估方法分别表征检出物的膳食暴露和健康指导值,安全风险评估风险系数分布在0.007%~9.4%之间,安全风险较低。结论 建立的食品接触材料安全评价方法是一种有效评价食品接触材料安全风险的方法,该方法具有一定的通用性,企业、行业和政府部门等可用于识别食品接触材料的安全风险,为减少和排除安全风险提供科学依据。 相似文献
53.
54.
Donggang Yu Author Vitae Tuan D. Pham Author Vitae Author Vitae Stephen T.C. Wong Author Vitae 《Pattern recognition》2009,42(4):498-508
Automated analysis of molecular images has increasingly become an important research in computational life science. In this paper some new and efficient algorithms for recognizing and analyzing cell phases of high-content screening are presented. The conceptual frameworks are based on the morphological features of cell nuclei. The useful preprocessing includes: smooth following and linearization; extraction of morphological structural points; shape recognition based morphological structure; issue of touching cells for cell separation and reconstruction. Furthermore, the novel detecting and analyzing strategies of feed-forward and feed-back of cell phases are proposed based on gray feature, cell shape, geometrical features and difference information of corresponding neighbor frames. Experiment results tested the efficiency of the new method. 相似文献
55.
56.
Huth J Buchholz M Kraus JM Mølhave K Gradinaru C v Wichert G Gress TM Neumann H Kestler HA 《Computer methods and programs in biomedicine》2011,104(2):227-234
The direct observation of cells over time using time-lapse microscopy can provide deep insights into many important biological processes. Reliable analyses of motility, proliferation, invasive potential or mortality of cells are essential to many studies involving live cell imaging and can aid in biomarker discovery and diagnostic decisions. Given the vast amount of image- and time-series data produced by modern microscopes, automated analysis is a key feature to capitalize the potential of time-lapse imaging devices. To provide fast and reproducible analyses of multiple aspects of cell behaviour, we developed TimeLapseAnalyzer. Apart from general purpose image enhancements and segmentation procedures, this extensible, self-contained, modular cross-platform package provides dedicated modalities for fast and reliable analysis of multi-target cell tracking, scratch wound healing analysis, cell counting and tube formation analysis in high throughput screening of live-cell experiments. TimeLapseAnalyzer is freely available (MATLAB, Open Source) at http://www.informatik.uni-ulm.de/ni/mitarbeiter/HKestler/tla. 相似文献
57.
58.
A rapid screening system for heterogeneous catalyst discovery has been developed by coupling an in-house designed and fabricated high temperature vapor phase pulse reactor on-line to a GC-MS. The incorporation of gas chromatography for separation of the products with the mass spectrometry system allowed simultaneous identification and determination of reaction products and substrate conversion. This system was employed to study the vapor phase catalytic hydride transfer reduction (CHTR) of nitrobenzene with methanol as hydrogen donor on an MgO catalyst as a model reaction. Structural information of all the by-products that were formed was useful to understand the reaction mechanism. The products obtained with the new screening technique were in good agreement with conventional bench scale experiments. The rapid online screening provided an efficient methodology for optimization of reaction conditions such as catalyst loading, reaction temperature, and mole ratios. Response Surface Methodology (RSM) was used to optimize the conversion of reactants and selectivity of products. 相似文献
59.
Ebenezer Danso-Amoako Miklas ScholzNickolas Kalimeris Qinli YangJunming Shao 《Computers, Environment and Urban Systems》2012
This study aims to provide a rapid screening tool for assessment of sustainable flood retention basins (SFRBs) to predict corresponding dam failure risks. A rapid expert-based assessment method for dam failure of SFRB supported by an artificial neural network (ANN) model has been presented. Flood storage was assessed for 110 SFRB and the corresponding Dam Failure Risk was evaluated for all dams across the wider Greater Manchester study area. The results show that Dam Failure Risk can be estimated by using the variables Dam Height, Dam Length, Maximum Flood Water Volume, Flood Water Surface Area, Mean Annual Rainfall (based on Met Office data), Altitude, Catchment Size, Urban Catchment Proportion, Forest Catchment Proportion and Managed Maximum Flood Water Volume. A cross-validation R2 value of 0.70 for the ANN model signifies that the tool is likely to predict variables well for new data sets. Traditionally, dams are considered safe because they have been built according to high technical standards. However, many dams that were constructed decades ago do not meet the current state-of-the-art dam design guidelines. Spatial distribution maps show that dam failure risks of SFRB located near cities are higher than those situated in rural locations. The proposed tool could be used as an early warning system in times of heavy rainfall. 相似文献
60.
This paper describes the results of a summative evaluation conducted to explore the usability and acceptability of an automated telephone-based technology, designed and developed as a screening tool for mental health disorders in the workplace. The system screens employees for symptoms and subsequently provides educational information and referrals to improve mental health and enhance productivity. The qualitative evaluation was a sub-study of a larger randomized controlled trial (RCT). We conducted in-depth interviews with 15 individuals who participated in the RCT and had used the system. A phenomenological theoretical framework was utilized to analyze the narrative data. Results indicated that participants had mostly positive experience with the system and perceived it as a confidential program that allowed them to reflect on their symptoms without inhibition, fear of judgment or embarrassment. We also learned that asking mere questions about mental health symptoms can be a positive, instructive and possibly a restorative experience. There is a likelihood that for many participants, exposure to questions about their emotional and mental distress validated their feelings about their symptoms and was sufficiently compelling to promote help-seeking behavior. This evaluation study demonstrates that computers can be utilized in the workplace as effective screening and educational tools to improve employees’ mental health. 相似文献