全文获取类型
收费全文 | 9123篇 |
免费 | 503篇 |
国内免费 | 142篇 |
专业分类
电工技术 | 319篇 |
综合类 | 196篇 |
化学工业 | 1812篇 |
金属工艺 | 220篇 |
机械仪表 | 243篇 |
建筑科学 | 529篇 |
矿业工程 | 111篇 |
能源动力 | 266篇 |
轻工业 | 561篇 |
水利工程 | 92篇 |
石油天然气 | 253篇 |
武器工业 | 14篇 |
无线电 | 839篇 |
一般工业技术 | 1387篇 |
冶金工业 | 1668篇 |
原子能技术 | 87篇 |
自动化技术 | 1171篇 |
出版年
2022年 | 108篇 |
2021年 | 168篇 |
2020年 | 133篇 |
2019年 | 109篇 |
2018年 | 155篇 |
2017年 | 155篇 |
2016年 | 196篇 |
2015年 | 218篇 |
2014年 | 250篇 |
2013年 | 574篇 |
2012年 | 407篇 |
2011年 | 452篇 |
2010年 | 384篇 |
2009年 | 361篇 |
2008年 | 438篇 |
2007年 | 393篇 |
2006年 | 384篇 |
2005年 | 331篇 |
2004年 | 280篇 |
2003年 | 275篇 |
2002年 | 308篇 |
2001年 | 215篇 |
2000年 | 187篇 |
1999年 | 192篇 |
1998年 | 151篇 |
1997年 | 156篇 |
1996年 | 166篇 |
1995年 | 128篇 |
1994年 | 108篇 |
1993年 | 115篇 |
1992年 | 110篇 |
1991年 | 96篇 |
1990年 | 89篇 |
1989年 | 102篇 |
1988年 | 90篇 |
1987年 | 94篇 |
1986年 | 92篇 |
1985年 | 104篇 |
1984年 | 120篇 |
1983年 | 93篇 |
1982年 | 83篇 |
1981年 | 93篇 |
1980年 | 67篇 |
1979年 | 103篇 |
1978年 | 70篇 |
1977年 | 78篇 |
1976年 | 67篇 |
1975年 | 70篇 |
1974年 | 60篇 |
1973年 | 75篇 |
排序方式: 共有9768条查询结果,搜索用时 15 毫秒
1.
Sangmin Lee Biao Che Meiling Tai Wanzhao Li Shin-Hyun Kim 《Advanced functional materials》2021,31(42):2105477
Hydrogel shells that compartmentalize the water core from the aqueous surrounding provide molecular selectivity on size and charge in transmembrane transport. It is highly demanding to produce thin hydrogel shells to minimize diffusion length and maximize core volume. Here, internal osmosis in water-in-oil-in-water-in-oil (W/O/W/O) triple-emulsion droplets is used to produce thin hydrogel shells enclosing a large water core. The triple-emulsion droplets are prepared to have an ultrathin middle oil layer using a capillary microfluidic device. The innermost water droplet has a higher osmolarity than the outer water layer containing photopolymerizable hydrogel precursors, which pumps water from the outer layer to the core through the ultrathin oil layer by the osmosis. Therefore, the outer layer gets thinner and hydrogel precursors are enriched while the size of the triple-emulsion droplets remains unchanged. Through photopolymerization of precursors and phase transfer from oil to water, hydrogel shells enclosing water core are produced in the water environment; the oil layer is ruptured for molecular exchange through the shells. The thickness and composition of the hydrogel shells are precisely controllable by the osmotic conditions. The shells show a high permeation rate due to the thinness as well as controlled cut-off threshold of permeation for neutral and charged molecules. 相似文献
2.
AbstractIndustry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel concept of developing experience-based virtual models of engineering entities, process, and the factory is presented. These models of production units, processes, and procedures are accomplished by virtual engineering object (VEO), virtual engineering process (VEP), and virtual engineering factory (VEF), using the knowledge representation technique of Decisional DNA. This blend of the virtual and physical domains permits monitoring of systems and analysis of data to foresee problems before they occur, develop new opportunities, prevent downtime, and even plan for the future by using simulations. Furthermore, the proposed virtual model concept not only has the capability of Query Processing and Data Integration for Industrial Data but also real-time visualization of data stream processing. 相似文献
3.
Aishwarya
Srivastava Siddhant Aggarwal Amy Apon Edward Duffy Ken Kennedy Andre Luckow Brandon Posey Marcin Ziolkowski 《Software》2020,50(6):868-898
We investigate the challenges of building an end-to-end cloud pipeline for real-time intelligent visual inspection system for use in automotive manufacturing. Current methods of visual detection in automotive assembly are highly labor intensive, and thus prone to errors. An automated process is sought that can operate within the real-time constraints of the assembly line and can reduce errors. Components of the cloud pipeline include capture of a large set of high-definition images from a camera setup at the assembly location, transfer and storage of the images as needed, execution of object detection, and notification to a human operator when a fault is detected. The end-to-end execution must complete within a fixed time frame before the next car arrives in the assembly line. In this article, we report the design, development, and experimental evaluation of the tradeoffs of performance, accuracy, and scalability for a cloud system. 相似文献
4.
Ming-Puu Chen Asta Y. Z. Lord Yu-Yao Cheng Ku-Chou Tai Wen-Harn Pan 《Journal of Computer Assisted Learning》2020,36(3):383-396
Reflective judgement is crucial for medical-related practitioners in dealing with controversial issues. However, the conformity phenomenon is likely to occur and interfere with reflective judgement learning during interactive activities. Effective strategies are required to moderate the conformity behaviour tendency (CBT) and improve reflective judgement performance (RJP). This study demonstrates two significant results: (a) Compared with the guided self-reflection learning strategy, the online collective reflection (OCR) learning strategy effectively weakened the learners' general CBT while dealing with professional controversial issues; and (b) a significantly negative correlation between the RJP achieved and the change of CBT in online environment was detected in the OCR group. The implications and potential applications in higher education were discussed. Further studies are needed to confirm the long-term effects and the extending application to other professional studies. 相似文献
5.
6.
7.
Dr. Li Di Prof. Per Artursson Dr. Alex Avdeef Prof. Leslie Z. Benet Prof. J. Brian Houston Dr. Manfred Kansy Edward H. Kerns Prof. Hans Lennernäs Dr. Dennis A. Smith Prof. Kiyohiko Sugano 《ChemMedChem》2020,15(20):1862-1874
Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug-drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure-permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients. 相似文献
8.
9.
10.