全文获取类型
收费全文 | 6106篇 |
免费 | 251篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 77篇 |
综合类 | 9篇 |
化学工业 | 1395篇 |
金属工艺 | 133篇 |
机械仪表 | 83篇 |
建筑科学 | 330篇 |
矿业工程 | 7篇 |
能源动力 | 121篇 |
轻工业 | 613篇 |
水利工程 | 36篇 |
石油天然气 | 8篇 |
武器工业 | 1篇 |
无线电 | 463篇 |
一般工业技术 | 1112篇 |
冶金工业 | 1212篇 |
原子能技术 | 61篇 |
自动化技术 | 697篇 |
出版年
2023年 | 42篇 |
2022年 | 66篇 |
2021年 | 101篇 |
2020年 | 75篇 |
2019年 | 76篇 |
2018年 | 104篇 |
2017年 | 103篇 |
2016年 | 153篇 |
2015年 | 139篇 |
2014年 | 158篇 |
2013年 | 223篇 |
2012年 | 228篇 |
2011年 | 279篇 |
2010年 | 252篇 |
2009年 | 219篇 |
2008年 | 243篇 |
2007年 | 209篇 |
2006年 | 220篇 |
2005年 | 153篇 |
2004年 | 161篇 |
2003年 | 153篇 |
2002年 | 137篇 |
2001年 | 142篇 |
2000年 | 128篇 |
1999年 | 139篇 |
1998年 | 380篇 |
1997年 | 275篇 |
1996年 | 186篇 |
1995年 | 109篇 |
1994年 | 103篇 |
1993年 | 103篇 |
1992年 | 69篇 |
1991年 | 53篇 |
1990年 | 68篇 |
1989年 | 58篇 |
1988年 | 41篇 |
1987年 | 47篇 |
1986年 | 49篇 |
1985年 | 42篇 |
1984年 | 44篇 |
1983年 | 43篇 |
1982年 | 47篇 |
1981年 | 41篇 |
1980年 | 42篇 |
1979年 | 45篇 |
1978年 | 42篇 |
1977年 | 81篇 |
1976年 | 94篇 |
1975年 | 38篇 |
1970年 | 28篇 |
排序方式: 共有6358条查询结果,搜索用时 15 毫秒
1.
Knaust Thiemo Felnhofer Anna Kothgassner Oswald D. Hllmer Helge Gorzka Robert-Jacek Schulz Holger 《Virtual Reality》2022,26(3):925-938
Virtual Reality - It is generally accepted that natural environments reduce stress and improve mood. Since access to natural environments is sometimes limited, virtual natural environments,... 相似文献
2.
Bilal Alashkar Alhamwe Daniel P. Potaczek Sarah Miethe Fahd Alhamdan Lukas Hintz Arslan Magomedov Holger Garn 《International journal of molecular sciences》2021,22(9)
Extracellular vesicles (EVs) are membranous structures, which are secreted by almost every cell type analyzed so far. In addition to their importance for cell-cell communication under physiological conditions, EVs are also released during pathogenesis and mechanistically contribute to this process. Here we summarize their functional relevance in asthma, one of the most common chronic non-communicable diseases. Asthma is a complex persistent inflammatory disorder of the airways characterized by reversible airflow obstruction and, from a long-term perspective, airway remodeling. Overall, mechanistic studies summarized here indicate the importance of different subtypes of EVs and their variable cargoes in the functioning of the pathways underlying asthma, and show some interesting potential for the development of future therapeutic interventions. Association studies in turn demonstrate a good diagnostic potential of EVs in asthma. 相似文献
3.
Simon Neumann Pin Hu Felix Bretschneider Holger Schmalz Andreas Greiner 《大分子材料与工程》2021,306(7):2100090
In this study, blends of the bio-based poly(limonene carbonate) (PLimC) with different commodity polymers are investigated in order to explore the potential of PLimC toward generating more sustainable polymer materials by reducing the amount of petro- or food-based polymers. PLimC is employed as minority component in the blends. Next to the morphology and thermal properties of the blends the impact of PLimC on the mechanical properties of the matrix polymers is studied. The interplay of incompatibility and zero-shear melt viscosity contrast determines the blend morphology, leading for all blends to a dispersed droplet morphology for PLimC. Blends with polymers of similar structure to PLimC (i.e., aliphatic/aromatic polyester) show the best performance with respect to mechanical properties, whereas blends with polystyrene or poly(methyl methacrylate) are too brittle and polyamide 12 blends show very low elongations at break. In blends with Ecoflex (poly(butylene adipate-co-terephthalate)) and Arnitel EM400 (copoly(ether ester)) with poly(butylene terephthalate) hard and polytetrahydrofuran soft segments) a threefold increase in E-modulus can be achieved, while keeping the elongation at break at reasonable high values of ≈200%, making these blends highly interesting for applications. 相似文献
4.
5.
6.
7.
8.
High‐intensity sweeteners in espresso coffee: ideal and equivalent sweetness and time–intensity analysis 下载免费PDF全文
Bruna M. Azevedo Flávio L. Schmidt Helena M. A. Bolini 《International Journal of Food Science & Technology》2015,50(6):1374-1381
The efficient substitution of sucrose by a sweetener in beverages requires the application of some sensory techniques. First, one must determine the concentrations of the sweeteners under study, equivalent in sweetness to the ideal sucrose concentration. In addition, it is fundamental to determine which is most similar to sucrose. The objectives of this study were to determine the ideal sweetness for espresso coffee and the equivalent concentrations in sweetness of different sweeteners, as well as characterise the time–intensity profile of each sweetener in relation to sweetness. The sweeteners evaluated were sucralose, aspartame, neotame, a cyclamate/saccharin mixture (2:1) and stevia. The sucrose concentration considered ideal by consumers was 12.5% (w/v), and the equivalent concentrations of the sweeteners were 0.0159% for sucralose, 0.0549% for aspartame, 0.0016% for neotame, 0.0359% for the cyclamate/saccharin mixture and 0.0998% for stevia. The time–intensity analysis indicated that possibly the sweeteners neotame, aspartame and sucralose would be the best substitutes for sucrose. 相似文献
9.
Freddy A. Bernal Dr. Marcel Kaiser Prof. Dr. Bernhard Wünsch Prof. Dr. Thomas J. Schmidt 《ChemMedChem》2020,15(1):68-78
Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub-tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate ester analogues and their structure-activity relationships. In general, Leishmania donovani and Trypanosoma brucei were quite susceptible to the compounds in a structure-dependent manner. Detailed analysis revealed a key role of the substitution pattern on the aromatic ring and a marked effect of the side chain on the activity against these two parasites. The high antileishmanial potency and remarkable selectivity of the nitro-aromatic derivatives suggested them as promising candidates for further studies. On the other hand, the high in vitro potency of catechol-type compounds against T. brucei could not be extrapolated to an in vivo mouse model. 相似文献
10.