全文获取类型
收费全文 | 318篇 |
免费 | 9篇 |
专业分类
电工技术 | 2篇 |
综合类 | 3篇 |
化学工业 | 98篇 |
金属工艺 | 3篇 |
机械仪表 | 2篇 |
建筑科学 | 20篇 |
能源动力 | 10篇 |
轻工业 | 78篇 |
水利工程 | 2篇 |
无线电 | 9篇 |
一般工业技术 | 44篇 |
冶金工业 | 11篇 |
自动化技术 | 45篇 |
出版年
2023年 | 4篇 |
2022年 | 22篇 |
2021年 | 17篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 9篇 |
2014年 | 17篇 |
2013年 | 15篇 |
2012年 | 13篇 |
2011年 | 20篇 |
2010年 | 17篇 |
2009年 | 17篇 |
2008年 | 19篇 |
2007年 | 15篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 12篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 5篇 |
排序方式: 共有327条查询结果,搜索用时 15 毫秒
261.
Angelika Lenz Philipp Arnold Reinhold Schneider Sabine Frick Yavuz Caydamli 《材料科学与工程:中英文B版...》2020,(2):74-83
The monitoring of mechanical deformation and damage of composite materials is normally performed by established analytical methods,such as strain gauges and opt... 相似文献
262.
263.
Previous research often regard household and individual as synonymous actors, although the overall household electricity consumption is the aggregate of diverging actions by individual household members. We disentangle the impact of actor-specific predictors on household and individual electricity consumption, employing regression models to data of 204 Austrian multi-person households. Predictors add more to the explained variance of household and individual electricity consumption if they are located at the same actor level as the dependent variable. While household electricity consumption is best predicted by the household context and value/knowledge factors, individual electricity consumption depends foremost on habit and whether a person stays at home during the day. The study exemplifies that future research and interventions need to decompose actor levels to better understand and target the drivers of private electricity consumption. Methodological challenges in measuring individual and household consumption behaviour are discussed. 相似文献
264.
265.
In the field of polymer technology, a variety of mainly synthetic additives are used to stabilize the materials during processing. However, natural compounds of plant origin can be a green alternative to chemicals such as synthetic polyphenols. An analysis of the effect of hesperidin on the aging behavior of ethylene-norbornene copolymer was performed. The evaluation of changes in the tested samples was possible by applying the following tests: determination of the surface energy and OIT values, mechanical properties analysis, colour change measurements, FT-IR and TGA analyses. The obtained results proved that hesperidin can be effectively used as natural stabilizer for polymers. Furthermore, as a result of this compound addition to Topas-silica composites, their surface and physico-mechanical properties have been improved and the resistance to aging significantly increased. Additionally, hesperidin can act as a dye or colour indicator and only few scientific reports describe a possibility of using flavonoids to detect changes in products during their service life, e.g., in food packaging. In the available literature, there is no information about the potential use of hesperidin as a stabilizer for cycloolefin copolymers. Therefore, this approach may contribute not only to the current state of knowledge, but also presents an eco-friendly solution that can be a good alternative to synthetic stabilizers. 相似文献
266.
Karsten Sammet Christoph Gastl Angelika Baro Sabine Laschat Peter Fischer Ina Fettig 《Advanced Synthesis \u0026amp; Catalysis》2010,352(13):2281-2290
Conjugate additions of Gilman cyanocuprates to (S)‐N‐amino‐2‐(methoxymethyl)pyrrolidine (SAMP)‐hydrazones 4 , 5 derived from cyclic and acyclic α,β‐unsaturated ketones were investigated. A protocol utilizing copper(II) sulfate/ammonium chloride was evolved, which allowed cleavage of SAMP (S)‐ 1 under the hydrolysis and work‐up conditions, followed by recovery of the auxiliary with ethylenediaminetetraacetic acid (EDTA). The enantioselectivity of cuprate additions was dominated for cyclic SAMP‐hydrazones 4 by the cuprate alkyl substituent and the ring size, in the case of acyclic arylidene SAMP‐hydrazones 5 , however, by the nature of the aryl substituent. Electron‐donating substituents gave poor enantiomeric excesses, whereas electron‐withdrawing groups provided excellent ee values of 98–99%. The configuration of the new stereocenter was determined to be (R). Moreover, a reaction sequence was developed which integrates a tandem 1,4‐addition/methylation and traceless hydrolytic cleavage of the auxiliary (S)‐ 1 in a one‐pot reaction, resulting in enantiomerically pure methyl ketones 11 – 13 , each of them with>99% ee. 相似文献
267.
The ɛ‐Amino Group of Protein Lysine Residues Is Highly Susceptible to Nonenzymatic Acylation by Several Physiological Acyl‐CoA Thioesters
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zeljko Simic Dr. Matthias Weiwad Dr. Angelika Schierhorn Dr. Clemens Steegborn Dr. Mike Schutkowski 《Chembiochem : a European journal of chemical biology》2015,16(16):2337-2347
Mitochondrial enzymes implicated in the pathophysiology of diabetes, cancer, and metabolic syndrome are highly regulated by acetylation. However, mitochondrial acetyltransferases have not been identified. Here, we show that acetylation and also other acylations are spontaneous processes that depend on pH value, acyl‐CoA concentration and the chemical nature of the acyl residue. In the case of a peptide derived from carbamoyl phosphate synthetase 1, the rates of succinylation and glutarylation were up to 150 times than for acetylation. These results were confirmed by using the protein substrate cyclophilin A (CypA). Deacylation experiments revealed that SIRT3 exhibits deacetylase activity but is not able to remove any of the succinyl groups from CypA, whereas SIRT5 is an effective protein desuccinylase. Thus, the acylation landscape on lysine residues might largely depend on the enzymatic activity of specific sirtuins, and the availability and reactivity of acyl‐CoA compounds. 相似文献
268.
269.
270.
Laundry washing has been extensively studied; laundry drying has been much less investigated. Nevertheless, there are indications that the drying process takes considerably more energy than the washing process. It is, therefore, the task of this study to gather European-wide consumer behaviour on washing and drying practices and to use this knowledge to estimate the energy consumption for the washing and drying processes. With an online questionnaire answered by over 2,000 households, the washing and drying behaviour of European consumers is analysed. The results also confirm the relevance of the drying process’ energy consumption for countries where the drying is normally seen as ‘done by the sun’! 相似文献