首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1289篇
  免费   76篇
  国内免费   53篇
电工技术   3篇
综合类   112篇
化学工业   709篇
金属工艺   30篇
机械仪表   13篇
建筑科学   7篇
矿业工程   12篇
能源动力   10篇
轻工业   142篇
水利工程   1篇
石油天然气   115篇
武器工业   1篇
无线电   12篇
一般工业技术   198篇
冶金工业   49篇
原子能技术   2篇
自动化技术   2篇
  2023年   8篇
  2022年   11篇
  2021年   14篇
  2020年   13篇
  2019年   19篇
  2018年   21篇
  2017年   20篇
  2016年   27篇
  2015年   28篇
  2014年   53篇
  2013年   61篇
  2012年   80篇
  2011年   74篇
  2010年   61篇
  2009年   66篇
  2008年   79篇
  2007年   125篇
  2006年   139篇
  2005年   105篇
  2004年   105篇
  2003年   89篇
  2002年   61篇
  2001年   24篇
  2000年   30篇
  1999年   29篇
  1998年   18篇
  1997年   11篇
  1996年   8篇
  1995年   13篇
  1994年   7篇
  1993年   2篇
  1992年   4篇
  1991年   5篇
  1990年   4篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
排序方式: 共有1418条查询结果,搜索用时 31 毫秒
11.
12.
Nao-Qing solution has been shown to be clinically effective in the treatment of acute ischemic stroke (AIS). The purpose of this study was to improve the pharmacokinetics and brain uptake of Nao-Qing, administered as an oil-in-water microemulsion. Sprague–Dawley (SD) rats were given Nao-Qing microemulsion by intranasal or intragastric routes. Samples of blood, brain, heart, liver, lung and kidney were collected at pre-determined time intervals, and the contents of ginsenosides Rg1 and Rb1 (active ingredients of the Nao-Qing microemulsion) were analyzed by high-performance liquid chromatography (HPLC). The results showed that contents of ginsenosides Rg1 and Rb1 in Nao-Qing microemulsion was 8475.13?±?54.61?μg/ml and 6633.42?±?527.27?μg/ml, respectively, and that the particle size, pH and viscosity of the microemulsion were 19.9?±?5.07?nm, 6.1 and 3.056?×?10?3?Pas, respectively. Absorption of ginsenoside Rg1 was higher than that of ginsenoside Rb1, which was barely detectable after intragastric administration; furthermore, the concentration of ginsenoside Rg1 in blood and other tissues at each time point was lower for intragastric than for intranasal administration. Compared with intragastric administration, intranasal administration resulted in a shorter tmax (0.08 versus 1?h), a higher Cmax (16.65 versus 11.29?μg/ml), and a higher area under the concentration–time curve (AUC) (592.91 versus 101.70?μg?h/ml) in the brain. The relative rates of uptake (Re) and the ratio of peak concentration (Ce) in the brain were 126.31% and 147.48% for ginsenoside Rg1, respectively. These data illustrate that intranasal administration can promote the absorption of drugs in Nao-Qing microemulsion and achieve fast effect.  相似文献   
13.
Context: The difference between the chemical polarities of the two categories of active chemical constituents in Chinese angelica volatile oil (CAVO) and Chinese angelica water extract (CAWE) greatly limit the development and clinical application of Chinese angelica preparation.

Object: The aim of this study is to design and prepare a “whole Chinese angelica” microemulsion (WCAM) that contains both CAVO and CAWE and at the same time to evaluate it in vivo and in vitro.

Materials and methods: CAVO and CAWE extracted from Chinese angelica were used as the oil and aqueous phases, respectively, to prepare the WCAM; its physicochemical property was observed, and its drug potency and oral bioavailability were evaluated.

Results: The formula of the WCAM was optimized as Tween-80:ethanol:CAVO:CAWE?=?3:3:1:40. The droplet size of the WCAM was 72.64?nm and the WCAM was proved to be physicochemically stable when it was kept at 0?°C, 4?°C, 25?°C and 40?°C for 3 months. The WCAM could markedly prolong blood clotting time, decrease whole blood viscosity and whole blood reduced viscosity at different shear rates, and improve hemorheological parameters. The results of the pharmacokinetic evaluation show that the AUC0–7 of the WCAM was 4510.66 and was about 4.41-fold compared to that of danggui concentrated pills (an existing Chinese angelica pharmaceutical preparation).

Conclusion: It can be concluded, that the WCAM is a promising Chinese angelica preparation that has great prospects in the treatment of dysmenorrhea and irregular menstruation.  相似文献   
14.
D相乳化法制备油墨清洗剂   总被引:1,自引:0,他引:1  
本文主要介绍了用D相乳化法制备一种特效油墨清洗剂,并对清洗剂性能进行了探讨,这种清洗剂主要成分由烷基酚聚氧乙烯醚、环保油溶剂、十二烷基苯磺酸钠以及水等组成。清洗剂为中性,主要用于清洗印刷操作工手上所沾油墨。这种清洗剂对人体皮肤无伤害,去油墨效果非常显著,且无毒无污染,价格低廉,制作简单,使用方便。  相似文献   
15.
Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method,and then deposited on Al2O3 to form the supported catalyst.The nanoparticles of Pd-Ag and Pd-Ag/Al2O3 samples were characterized by UV/Vis,HRTEM,EDX,XRD,and XPS.The test results indicated that Pd-Ag bimetallic alloy nanoparticles with a size of about 2 nm and a face-centered cubic(fcc) structure were formed in the measured area of microemulsion.The growth of nanoparticles was effectively limited within the droplet of micoremulsion.TEM image exhibited that the Pd-Ag alloy nanoparticles were well-dispersed on the Al2O3 support.The catalytic performance of various catalysts for selective hydrogenation of acetylene showed that a higher acetylene conversion and selectivity to ethylene upon acetylene hydrogenation was achieved on a nano-sized Pd-Ag bimetallic catalyst with a Pd/Ag alloy supported molar ratio of 1:1.5.  相似文献   
16.
介绍了-10<'#>,0<'#>柴油微乳液的组成,确定了柴油、水、表面活性剂的质量配比,采用超声波处理为分散手段制备了微乳化柴油;并将-10<'#>柴油制备的微乳液与0<'#>柴油制备的微乳液作了对比;对制得的微乳化柴油的十六烷值、闪点、密度、黏度、粒径、凝点、热值、胶质质量浓度等理化性能指标进行了测定与分析对比;同时...  相似文献   
17.
咪鲜胺和三唑酮复配有一定的增效作用,本实验通过拟三相图对非离子与阴离子表面活性剂不同复配比例的选择和对乳化剂、溶剂、助溶剂、水质等的筛选,确定最佳的配方组合,并对该配方的剂型进行了质量指标的测试。  相似文献   
18.
Polystyrene/carbon nanotubes composites were readily prepared by reversed microemulsion polymerization. Compared with the composites prepared by solution mixing, the uniform dispersion of carbon nanotubes in polymer matrix could be obtained more easily and the thermal and electrical properties of the as‐prepared composites were also enhanced. The as‐prepared composites were deposited onto a microelectrode array to fabricate a vapor sensor. The response for different organic vapors was evaluated by monitoring the change in the resistance of the composites upon exposure to various gases. The change in resistance was of the order of about 103 for the composites prepared by reversed microemulsion polymerization. The chemical sensors based on the composites prepared by reversed microemulsion polymerization presented excellent reproducibility and reversibility in response. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   
19.
乳化剂对丙烯酸酯微乳液聚合过程的影响   总被引:3,自引:0,他引:3  
采用半连续单体滴加法合成了粒径约40 nm分布均一的丙烯酸酯微乳液.考察了乳化剂的种类、配比、用量及反应型乳化剂V -20S的引入对乳液及涂膜性能的影响,跟踪测试了乳液聚合过程中粒径的变化,探讨了聚合过程中不同阶段的粒径大小和分布变化.结果表明:以MS - 1/SDS/OP - 10为乳化剂且质量比为0.7∶0.2∶0...  相似文献   
20.
以苯乙烯、丙烯酸酯类为聚合性单体,采用核壳微乳液聚合方法合成了具有硬核软壳结构的纳米聚合物微乳液,加入纳米负离子粉,制成了可产生负离子的汽车地毯背衬胶黏剂,对负离子产生的数量和速率进行了表征,并对胶黏剂的成膜及热性能进行了研究。结果表明:20%.30%的负离子粉含量可在100s内使负离子浓度达到平衡,聚合物微粒的硬核软壳结构有利于成膜并保持良好的耐热性。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号