全文获取类型
收费全文 | 15510篇 |
免费 | 1890篇 |
国内免费 | 641篇 |
专业分类
电工技术 | 3705篇 |
技术理论 | 1篇 |
综合类 | 1129篇 |
化学工业 | 3266篇 |
金属工艺 | 480篇 |
机械仪表 | 253篇 |
建筑科学 | 1022篇 |
矿业工程 | 2100篇 |
能源动力 | 317篇 |
轻工业 | 2007篇 |
水利工程 | 149篇 |
石油天然气 | 573篇 |
武器工业 | 78篇 |
无线电 | 480篇 |
一般工业技术 | 907篇 |
冶金工业 | 1029篇 |
原子能技术 | 91篇 |
自动化技术 | 454篇 |
出版年
2024年 | 55篇 |
2023年 | 251篇 |
2022年 | 481篇 |
2021年 | 636篇 |
2020年 | 552篇 |
2019年 | 391篇 |
2018年 | 391篇 |
2017年 | 523篇 |
2016年 | 560篇 |
2015年 | 669篇 |
2014年 | 843篇 |
2013年 | 842篇 |
2012年 | 1070篇 |
2011年 | 1172篇 |
2010年 | 861篇 |
2009年 | 907篇 |
2008年 | 788篇 |
2007年 | 1168篇 |
2006年 | 1018篇 |
2005年 | 881篇 |
2004年 | 733篇 |
2003年 | 586篇 |
2002年 | 461篇 |
2001年 | 426篇 |
2000年 | 361篇 |
1999年 | 290篇 |
1998年 | 233篇 |
1997年 | 147篇 |
1996年 | 118篇 |
1995年 | 115篇 |
1994年 | 110篇 |
1993年 | 65篇 |
1992年 | 86篇 |
1991年 | 60篇 |
1990年 | 48篇 |
1989年 | 21篇 |
1988年 | 24篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1976年 | 2篇 |
1966年 | 2篇 |
1959年 | 2篇 |
1958年 | 3篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Effect of complexation of oxidised corn starch with mineral elements on physicochemical properties 下载免费PDF全文
Sławomir Pietrzyk Teresa Fortuna Lesław Juszczak Dorota Gałkowska Karolina Królikowska Karolina Zięba 《International Journal of Food Science & Technology》2015,50(4):934-941
The objective of this study was to determine the effect of complexation of oxidised starch with mineral elements on its physicochemical properties. Corn starch was oxidised with sodium hypochlorite and, afterwards, modified with ions of potassium, magnesium and iron. Thus, native and modified starches were analysed for: contents of mineral elements, colour parameters (L*a*b*), water binding capacity and solubility in water at temperature of 60 and 80 °C. Thermodynamic characteristics of gelatinisation by DSC, molecular weight distribution by GPC, intrinsic viscosity and pasting properties by RVA were studied. The efficiency of incorporation of metal ions into oxidised corn starch was about 30%, 20% and 20% for potassium, magnesium and iron ions, respectively. The complexation with potassium ions caused the greatest changes in the molecular weight distribution and the intrinsic viscosity of starches and viscosity of starch pastes. Only modification of starch with iron ions affected the colour parameters of the starch. Incorporation of metal ions into starch resulted also in changes in its water binding capacity and solubility in water. 相似文献
2.
电力系统谐波检测的现状与发展 总被引:7,自引:0,他引:7
准确、实时地对电力系统谐波进行检测有着重要的意义。本文根据电力系统谐波测量的基本方法,对近年来电力系统谐波检测的新方法进行了分析和评述。最后对电力系统的谐波测量进行了总结并提出了看法。 相似文献
3.
A batch reactor may be combined directly with a distillation column by distilling off the light component product in order to increase the reactor temperature or to improve the product yield of an equilibrium reaction. The same amount of the light product should be removed as the amount being formed by the reaction at any time. A linearized model has been developed which describes the process behaviour satisfactorily for control analysis purposes. The controllability of a combined batch reactor/batch distillation column is found to depend strongly on the operating conditions and on the time during the run. In general, controlling only the reactor temperature (one-point bottom control) is difficult since the set-point has to be specified below a maximum value in order to avoid break-through of an intermediate component in the ditillate. This maximum value may be difficult to know a priori. For the example considered in this study, control of both reactor temperature and distillate composition (two-point control) is also found to be difficult due to large interactions in the column. As with one-point bottom control, the reactor temperature has to be specified below a maximum value. However, energy can be saved since the heat duty can be decreased with time. Controlling the temperature on a tray in the column (one-point column control) is found to give good performance for the given process with no loss of reactant and a high reactor temperature, although no direct control of the reactor temperature is obtained. 相似文献
4.
晋北吕梁群石榴石的特征及指示意义 总被引:5,自引:0,他引:5
石榴石是山西岚县袁家村一带-娄烦县出露的吕梁群地层中主要的特征变质矿物,其次为黑云母、十字石等,对这些特征变质矿物进行电子探针的成分分析及其相关计算,并利用不同采样点的矿物对估算该点变质温度和压力,最后得到石榴石的成分变化与变质程度之间的关系,进而阐明了石榴石中成分变化对变质温度与压力的指示意义。 相似文献
5.
6.
数据包络分析模型及其应用研究 总被引:1,自引:1,他引:0
郑明贵 《南方冶金学院学报》2004,25(4):62-66
通过对传统的C^2R模型进行研究并加以改进,建立了C2RHZ模型,利用有色金属矿采选业1993-2001年科技创新的相关数据进行了计算分析。说明了C^2RHZ模型的应用价值. 相似文献
7.
Permeable reactive barrier for groundwater remediation 总被引:4,自引:0,他引:4
R. Thiruvenkatachari S. Vigneswaran R. Naidu 《Journal of Industrial and Engineering Chemistry》2008,14(2):145-156
This article aims to provide an overview of the upcoming technology of permeable reactive barriers for groundwater remediation. A comprehensive list of references and web-links are also provided for further in-depth understanding. A brief discussion on the Australian perspective on this emerging technology is also included. 相似文献
8.
Thecokesolutionlossreactionisoneofthemostimportanteffectsresultingincokepulverizinginblastfurnace .Thefactorswhichaffectreactionincludecokeporestructure ,micro crystalstructureonporewall ,thecontentandconstituentofminer als ,etc .Amongthesefactors ,theconstituentofmineralsisemphasizedallovertheworldinrecentyears .Buttheemphasisofmoststudieswasputontheeffectofalkalimetals (K ,Na)oncokesolutionlossreactionandtheeffectofotherelementswassel domreported[1-5] .Theeffectofthirteenmineralsoncokesolut… 相似文献
9.
SIMADYN D控制器应用于动态无功补偿,标志武钢动态无功补偿控制实现数字化突破。提高了系统的可靠性、调节精度和动态指标。 相似文献
10.
Eugene Jarosewich 《Journal of research of the National Institute of Standards and Technology》2002,107(6):681-685
This is a short history of the Smithsonian Microbeam Standards; their sources, selection, preparation, and analyses. Fifty-eight minerals, natural glasses, and synthetic samples have been characterized in the past 25 years. During that time, over 750 requests were received for approximately 11 000 individual samples. These reference samples are referred to as the Smithsonian Microbeam Standards. 相似文献