全文获取类型
收费全文 | 2137篇 |
免费 | 70篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 31篇 |
综合类 | 1篇 |
化学工业 | 655篇 |
金属工艺 | 46篇 |
机械仪表 | 39篇 |
建筑科学 | 79篇 |
矿业工程 | 2篇 |
能源动力 | 66篇 |
轻工业 | 171篇 |
水利工程 | 12篇 |
石油天然气 | 6篇 |
无线电 | 220篇 |
一般工业技术 | 394篇 |
冶金工业 | 216篇 |
原子能技术 | 16篇 |
自动化技术 | 254篇 |
出版年
2021年 | 35篇 |
2020年 | 13篇 |
2019年 | 19篇 |
2018年 | 33篇 |
2017年 | 36篇 |
2016年 | 41篇 |
2015年 | 18篇 |
2014年 | 54篇 |
2013年 | 108篇 |
2012年 | 90篇 |
2011年 | 112篇 |
2010年 | 84篇 |
2009年 | 102篇 |
2008年 | 98篇 |
2007年 | 98篇 |
2006年 | 81篇 |
2005年 | 70篇 |
2004年 | 62篇 |
2003年 | 62篇 |
2002年 | 74篇 |
2001年 | 33篇 |
2000年 | 32篇 |
1999年 | 38篇 |
1998年 | 51篇 |
1997年 | 48篇 |
1996年 | 43篇 |
1995年 | 40篇 |
1994年 | 34篇 |
1993年 | 35篇 |
1992年 | 31篇 |
1991年 | 34篇 |
1990年 | 36篇 |
1989年 | 29篇 |
1988年 | 24篇 |
1987年 | 27篇 |
1986年 | 25篇 |
1985年 | 42篇 |
1984年 | 34篇 |
1983年 | 18篇 |
1982年 | 26篇 |
1981年 | 20篇 |
1980年 | 17篇 |
1979年 | 29篇 |
1978年 | 23篇 |
1977年 | 24篇 |
1976年 | 22篇 |
1975年 | 22篇 |
1974年 | 14篇 |
1973年 | 18篇 |
1971年 | 11篇 |
排序方式: 共有2208条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Claudia Anahite Ovando Julio Cesar de Carvalho Gilberto Vinícius de Melo Pereira Philippe Jacques Vanete Thomaz Soccol 《Food Reviews International》2018,34(1):34-51
Bioactive peptides represent specific sequences of amino acids that have biological activity with several health effects and potential applications, which can be obtained from diverse protein sources. Spirulina, the cyanobacterium known for its high protein content and therapeutic properties, has been investigated as a potential source of bioactive peptides. Some bioactive peptides derived from Spirulina are under study for their ability to offer specific health benefits, such as antimicrobial, antiallergic, antihypertensive, antitumor, and immunomodulatory properties. Bioactive peptide fractions from Spirulina biomass can be obtained through a series of operations, including cell lysis and protein extraction, enzymatic hydrolysis, potential bioactivity screening, fractionation, and purification. Potentially, Spirulina-derived peptide fractions can be applied as nutraceutical ingredients in foods and pharmaceuticals. This article reviews the functional properties and health benefits of bioactive peptides from Spirulina, and presents potential mechanisms by which bioactive components can be exploited in the development of novel foods with special health claims. In addition, this article describes recent developments in proteomics, bioactivity screening methods, and opportunities for designing future peptide-based foods. 相似文献
5.
Magnetic Resonance Materials in Physics, Biology and Medicine - To show the relevance of a simple finite difference transmission line model to help design safe implanted cables in 1.5T MRI’s... 相似文献
6.
A. Baux S. Jacques A. Allemand G.L. Vignoles P. David T. Piquero M.-P. Stempin G. Chollon 《Journal of the European Ceramic Society》2021,41(6):3274-3284
We present here an original route for the manufacturing of SiC ceramics based on 3D printing, polymer impregnation and pyrolysis and chemical vapor deposition (CVD). The green porous elastomer structures were first prepared by fused deposition modeling (FDM) 3D-printing with a composite polyvinyl alcohol/elastomer wire and soaking in water, then impregnated with an allylhydridopolycarbosilane preceramic polymer. After crosslinking and pyrolysis, the polymer-derived ceramics were reinforced by CVD of SiC using CH3SiCl3/H2 as precursor. The multiscale structure of the SiC porous specimens was examined by X-ray tomography and scanning electron microscopy analyses. Their oxidation resistance was also studied. The pure and dense CVD-SiC coating considerably improves the oxidation resistance. 相似文献
7.
Neuropathological lesions in Alzheimer’s disease (AD) include amyloid plaques formed by the accumulation of amyloid peptides, neurofibrillary tangles made of hyperphosphorylated tau protein, synaptic and neuronal degenerations, and neuroinflammation. The cause of AD is unknown, but according to the amyloid hypothesis, amyloid oligomers could lead to the activation of kinases such as eukaryotic translation initiation factor 2-alpha kinase 2 (PKR), p38, and receptor-interacting serine/threonine-protein kinase 1 (RIPK1), which all belong to the same stress-activated pathway. Many toxic kinase activations have been described in AD patients and in experimental models. A p38 mitogen-activated protein kinase inhibitor was recently tested in clinical trials but with unsuccessful results. The complex PKR/P38/RIPK1 (PKR/dual specificity mitogen-activated protein kinase kinase 6 (MKK6)/P38/MAP kinase-activated protein kinase 2 (MK2)/RIPK1) is highly activated in AD brains and in the brains of AD transgenic animals. To delineate the implication of this pathway in AD, we carried out a search on PubMed including PKR/MKK6/p38/MK2/RIPK1, Alzheimer, and therapeutics. The involvement of this signaling pathway in the genesis of AD lesions, including Aβ accumulations and tau phosphorylation as well as cognitive decline, is demonstrated by the reports described in this review. A future combination strategy with kinase inhibitors should be envisaged to modulate the consequences for neurons and other brain cells linked to the abnormal activation of this pathway. 相似文献
8.
Bulletin of Engineering Geology and the Environment - Un appareil appelé SAIGNOFOR a été développé pour évaluer la résistance à la compression des terrains... 相似文献
9.
Biological hazards associated with the collection of solid and compostable waste have not been well characterized in North America. This is an issue because workers who handle such materials may be exposed to bioaerosols (airborne bacteria and fungi) and dusts resulting in infections or allergic diseases. We conducted a personal sampling campaign for culturable bacteria and fungi in the breathing zones of waste collectors in a variety of typical work settings (scenarios) in the province of Quebec, Canada. Total culturable bacterial and fungal counts were analyzed and compared to ambient environmental levels (background) to determine the degree of incremental exposure among workers. In several scenarios, worker exposure counts were significantly (p < or = 0.05) higher than ambient levels measured upwind, with the highest personal exposures to bacteria observed for urban compostable waste collectors (median = 50,300 Colony Forming Units/m(3) of air (CFU/m(3))). On the other hand, fungal counts collected on an every-other-week cycle were highest among a group of rural compostable waste collectors (median = 101,700 CFU/m(3)). Similar exposures to culturable bacteria and fungi have been reported in European workers who showed such adverse health effects as nausea, diarrhea, upper respiratory tract irritation, and allergy. Therefore, it may be necessary to modify certain work practices in order to minimize exposure. Recommendations include automation of waste and compost collection, use of personal protective equipment including goggles, gloves, and disposable masks, and meticulous personal hygiene. 相似文献
10.
Pierre Yves Le Gac Morgane Broudin Gérard Roux Jacques Verdu Peter Davies Bruno Fayolle 《Polymer》2014
Tensile properties and crack propagation properties, especially critical strain energy release rate in mode I, GIC, have been used to investigate fracture properties of elastomers and their relationships with microstructure. These investigations were mainly based on a series of comparisons: first, the behaviour of polychloroprene rubber (CR), undergoing stress hardening due to strain induced crystallization (SIC) and oxidative crosslinking (OCL) was compared with that of chlorinated polyethylene (CPE), which undergoes SIC but not OCL, and with a polyurethane based on hydroxyl terminated polybutadiene (PU) which undergoes OCL but not SIC. Comparisons were also made on CR between fracture behaviour at ambient temperature, where SIC occurs and at 100 °C where there is no SIC. Finally, oxidative crosslinking was used to vary in a continuous way the crosslink density in CR and PU, in order to evaluate the role of crosslinking in fracture behaviour. 相似文献