全文获取类型
收费全文 | 8672篇 |
免费 | 518篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 96篇 |
综合类 | 8篇 |
化学工业 | 2353篇 |
金属工艺 | 114篇 |
机械仪表 | 251篇 |
建筑科学 | 380篇 |
矿业工程 | 21篇 |
能源动力 | 369篇 |
轻工业 | 1507篇 |
水利工程 | 94篇 |
石油天然气 | 38篇 |
无线电 | 537篇 |
一般工业技术 | 1326篇 |
冶金工业 | 345篇 |
原子能技术 | 49篇 |
自动化技术 | 1718篇 |
出版年
2024年 | 20篇 |
2023年 | 96篇 |
2022年 | 298篇 |
2021年 | 374篇 |
2020年 | 262篇 |
2019年 | 309篇 |
2018年 | 360篇 |
2017年 | 328篇 |
2016年 | 401篇 |
2015年 | 306篇 |
2014年 | 425篇 |
2013年 | 720篇 |
2012年 | 592篇 |
2011年 | 706篇 |
2010年 | 463篇 |
2009年 | 522篇 |
2008年 | 451篇 |
2007年 | 396篇 |
2006年 | 332篇 |
2005年 | 269篇 |
2004年 | 236篇 |
2003年 | 186篇 |
2002年 | 186篇 |
2001年 | 95篇 |
2000年 | 79篇 |
1999年 | 68篇 |
1998年 | 100篇 |
1997年 | 64篇 |
1996年 | 66篇 |
1995年 | 62篇 |
1994年 | 47篇 |
1993年 | 44篇 |
1992年 | 38篇 |
1991年 | 34篇 |
1990年 | 30篇 |
1989年 | 28篇 |
1988年 | 20篇 |
1987年 | 24篇 |
1986年 | 18篇 |
1985年 | 24篇 |
1984年 | 24篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 8篇 |
1980年 | 14篇 |
1979年 | 7篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 5篇 |
排序方式: 共有9206条查询结果,搜索用时 0 毫秒
1.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage 下载免费PDF全文
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
2.
Cuevas-Glory Luis F. Sosa-Moguel Odri Pino Jorge Sauri-Duch Enrique 《Food Analytical Methods》2015,8(4):1005-1013
Food Analytical Methods - The habanero pepper (Capsicum chinense Jacq.) is very aromatic and is the hottest pepper in the world. In this study, a headspace solid-phase microextraction/gas... 相似文献
3.
4.
5.
6.
Mobile software applications have to cope with a particular environment that involves small size, limited resources, high autonomy requirements, competitive business models and many other challenges. To provide development guidelines that respond to these needs, several practices have been introduced; however, it is not clear how these guidelines may contribute to solve the issues present in the mobile domain. Furthermore, the rapid evolution of the mobile ecosystem challenges many of the premises upon which the proposed practices were designed. In this paper, we present a survey of the literature on software assurance practices for mobile applications, with the objective of describing them and assessing their contribution and success. We identified, organized and reviewed a body of research that spans in three levels: software development processes, software product assurance practices, and software implementation practices. By carrying out this literature survey, we reviewed the different approaches that researchers on Software Engineering have provided to address the needs that raise in the mobile software development arena. Moreover, we review the evolution of these practices, identifying how the constant changes and modernization of the mobile execution environment has impacted the methods proposed in the literature. Finally, we introduced discussion on the application of these practices in a real productive setting, opening an area for further research that may determine if practitioners have followed the proposed assurance paradigms. 相似文献
7.
Luca Pietrobon Lorenzo Fallarino Andreas Berger Andrey Chuvilin Flix Casanova Luis E. Hueso 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(47):6295-6301
Graphene has been predicted to develop a magnetic moment by proximity effect when placed on a ferromagnetic film, a promise that could open exciting possibilities in the fields of spintronics and magnetic data recording. In this work, the interplay between the magnetoresistance of graphene and the magnetization of an underlying ferromagnetic insulating film is studied in detail. A clear correlation between both magnitudes is observed but through a careful modeling of the magnetization and the weak localization measurements, that such correspondence can be explained by the effects of the magnetic stray fields arising from the ferromagnetic insulator is found. The results emphasize the complexity arising at the interface between magnetic and 2D materials. 相似文献
8.
Precil Diego M. M. Neves Fernanda M. Freitas Christiane A. Kojima Beatriz L. Carmello Rodrigo Bazan Pasqual Barretti Luis C. Martin 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(1):143-145
Antibiotics are potentially a cause of neurotoxicity in dialysis patients, the most common are the beta‐lactams as ceftazidime and cefepime, and few cases have been reported after piperacillin/tazobactam use. This report presents a case of a hypertensive and diabetic 67‐year‐old woman in regular hemodialysis, which previously had a stroke. She was hospitalized presenting pneumonia, which was initially treated with cefepime. Two days after treatment, she presented dysarthria, left hemiparesis, ataxia, and IX and X cranial nerves paresis. Computed tomography showed no acute lesions and cefepime neurotoxicity was hypothesized, and the antibiotic was replaced by piperacillin/tazobactam. The neurologic signs disappeared; however, 4 days after with piperacillin/tazobactam treatment, the neurological manifestations returned. A new computed tomography showed no new lesions, and the second antibiotic regimen withdrawn. After two hemodialysis sessions, the patient completely recovered from neurological manifestations. The patient presented sequentially neurotoxicity caused by two beta‐lactams antibiotics. This report meant to alert clinicians that these antibiotics have dangerous neurological effects in chronic kidney disease patients. 相似文献
9.
10.
Demiguel S. Giraudet L. Joulaud L. Decobert J. Blache F. Coupe V. Jorge F. Pagnod-Rossiaux P. Boucherez E. Achouche M. Devaux F. 《Lightwave Technology, Journal of》2002,20(12):2004-2014
The design, fabrication, and performance of double-stage taper photodiodes (DSTPs) are reported. The objective of this work is to develop devices compatible with 40-Gb/s applications. Such devices require high efficiency, ultrawide band, high optical power handling capability, and compatibility with low-cost module fabrication. The integration of mode size converters improves both the coupling efficiency and the responsivity with a large fiber mode diameter. Responsivity of 0.6 A/W and 0.45 A/W are achieved with a 6-/spl mu/m fiber mode diameter and cleaved fiber, respectively, providing relaxed alignment tolerances (/spl plusmn/1.6 /spl mu/m and /spl plusmn/2 /spl mu/m, respectively), compatible with cost-effective packaging techniques. DSTPs also offer a wide bandwidth greater than 40 GHz and transverse-electric/transverse-magnetic polarization dependence lower than 0.2 dB. Furthermore, a DSTP saturation current as high as 11 mA results in optical power handling greater than +10 dBm and a high output voltage of 0.8 V. These capabilities allow the photodiode to drive the decision circuit without the need of a broad-band electrical amplifier. The DSTP devices presented here demonstrate higher responsivities with large fiber mode diameter and better optical power handling capabilities and are compared with classical side-illuminated photodiodes. 相似文献