全文获取类型
收费全文 | 461篇 |
免费 | 34篇 |
专业分类
综合类 | 6篇 |
化学工业 | 146篇 |
金属工艺 | 6篇 |
机械仪表 | 3篇 |
建筑科学 | 27篇 |
能源动力 | 13篇 |
轻工业 | 78篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 12篇 |
一般工业技术 | 65篇 |
冶金工业 | 61篇 |
原子能技术 | 1篇 |
自动化技术 | 71篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 28篇 |
2021年 | 22篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 24篇 |
2015年 | 15篇 |
2014年 | 22篇 |
2013年 | 29篇 |
2012年 | 34篇 |
2011年 | 49篇 |
2010年 | 23篇 |
2009年 | 34篇 |
2008年 | 24篇 |
2007年 | 16篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 8篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有495条查询结果,搜索用时 15 毫秒
61.
Sonja Bauer Justus Behnisch Anna Dell Achim Gahr Michael Leinhos Hans Joachim Linke Weimin Shen Johanna Tolksdorf Martin Wagner 《化学,工程师,技术》2019,91(10):1472-1479
Water shortage is often a challenge for industrial park developments. To ensure a more sustainable water supply, the Industrial Wastewater Management Concept with a focus on Reuse (IW2MC→R) provides a strategy to meet the challenges. Main requirements to achieve water reuse fit for purpose are optimized wastewater treatment, an optimized sewer and pipe system, and an innovative water quality monitoring concept. To evaluate water‐reuse concepts, a reuse factor is calculated, which relates to all wastewater inflows to the central wastewater treatment plant and all reuse‐water flows. 相似文献
62.
Pier Giorgio Peiretti Claudio Medana Sonja Visentin Valeria Giancotti Valentina Zunino Giorgia Meineri 《Food chemistry》2011
The aim of this research was to determine the content of the histidinic antioxidants, advanced glycation end products (pentosidine) and thiobarbituric acid reactive substance (TBARS) in the meat from different animal species. Carnosine, anserine, homocarnosine and pentosidine were quantified by HPLC/MS, while TBARS was determined by photometric measurements. The total CRCs (carnosine + anserine + homocarnosine) content was in the increasing order: beef < rabbit < pork < horse < chicken < turkey. The analysis showed traces of pentosidine above the instrumental determination limits in all the meat samples, while the susceptibility of these meat to lipid oxidation decreased from beef to chicken, with the exception of turkey meat, which presented a high TBARS content towards even though its total CRCs was the highest. The structure of homocarnosine was elucidated by high resolving power multistage mass spectrometry. 相似文献
63.
Kris Van Looy Jonathan D. Tonkin Mathieu Floury Catherine Leigh Janne Soininen Stefano Larsen Jani Heino N. LeRoy Poff Michael Delong Sonja C. Jhnig Thibault Datry Núria Bonada Juliette Rosebery Aurlien Jamoneau Steve J. Ormerod Kevin J. Collier Christian Wolter 《河流研究与利用》2019,35(2):107-120
Resilience in river ecosystems requires that organisms must persist in the face of highly dynamic hydrological and geomorphological variations. Disturbance events such as floods and droughts are postulated to shape life history traits that support resilience, but river management and conservation would benefit from greater understanding of the emergent effects in communities of river organisms. We unify current knowledge of taxonomic‐, phylogenetic‐, and trait‐based aspects of river communities that might aid the identification and quantification of resilience mechanisms. Temporal variations in river productivity, physical connectivity, and environmental heterogeneity resulting from floods and droughts are highlighted as key characteristics that promote resilience in these dynamic ecosystems. Three community‐wide mechanisms that underlie resilience are (a) partitioning (competition/facilitation) of dynamically varying resources, (b) dispersal, recolonization, and recruitment promoted by connectivity, and (c) functional redundancy in communities promoted by resource heterogeneity and refugia. Along with taxonomic and phylogenetic identity, biological traits related to feeding specialization, dispersal ability, and habitat specialization mediate organism responses to disturbance. Measures of these factors might also enable assessment of the relative contributions of different mechanisms to community resilience. Interactions between abiotic drivers and biotic aspects of resource use, dispersal, and persistence have clear implications for river conservation and management. To support these management needs, we propose a set of taxonomic, phylogenetic, and life‐history trait metrics that might be used to measure resilience mechanisms. By identifying such indicators, our proposed framework can enable targeted management strategies to adapt river ecosystems to global change. 相似文献
64.
Antonia Loibl Frank Marscheider-Weidemann Katrin Ostertag Sonja Rosenberg Luis Tercero Espinoza Matthias Pfaff Christian Sartorius 《化学,工程师,技术》2020,92(4):414-422
The socio-economic and ecological impacts of selected projects of the BMBF funding program “r4 – Innovative Technologies for Resource Efficiency – Research for the Provision of Raw Materials of Strategic Economic Importance” are presented. Many, but not all, research projects indicate a potential improvement of the supply situation in Germany. In some cases, the provision of secondary raw materials is unprofitable or ecologically detrimental. These cases require a balancing between security of supply and other economic and ecological objectives. 相似文献
65.
66.
Simona Dimchevska Nikola Geskovski Gjorgji Petruševski Marina Chacorovska Riste Popeski-Dimovski Sonja Ugarkovic 《Drug development and industrial pharmacy》2017,43(3):502-510
One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers. D-optimal design was applied to optimize PLGA/PCL ratio in the polymer blend and the mode of addition of the amphiphilic copolymer Lutrol®F127 in order to maximize SN-38 loading and obtain NPs with acceptable size for passive tumor targeting. Drug/polymer and polymer/polymer interaction analysis pointed to high degree of compatibility and miscibility among both hydrophobic polymers, providing core configuration with higher drug loading capacity. Toxicity studies outlined the biocompatibility of the blank NPs. Increased in vitro efficacy of drug-loaded NPs compared to the free drug was confirmed by growth inhibition studies using SW-480 cell line. Additionally, the optimized NP formulation showed very promising blood circulation profile with elimination half-time of 7.4?h. 相似文献
67.
Paul Strasser Bianca Montsch Silvia Weiss Haider Sami Christoph Kugler Sonja Hager Hemma Schueffl Robert Mader Oliver Brüggemann Christian R. Kowol Manfred Ogris Petra Heffeter Ian Teasdale 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(22):2300767
Bottlebrush polymers are highly promising as unimolecular nanomedicines due to their unique control over the critical parameters of size, shape and chemical function. However, since they are prepared from biopersistent carbon backbones, most known bottlebrush polymers are non-degradable and thus unsuitable for systemic therapeutic administration. Herein, we report the design and synthesis of novel poly(organo)phosphazene-g-poly(α-glutamate) (PPz-g-PGA) bottlebrush polymers with exceptional control over their structure and molecular dimensions (Dh ≈ 15–50 nm). These single macromolecules show outstanding aqueous solubility, ultra-high multivalency and biodegradability, making them ideal as nanomedicines. While well-established in polymer therapeutics, it has hitherto not been possible to prepare defined single macromolecules of PGA in these nanosized dimensions. A direct correlation was observed between the macromolecular dimensions of the bottlebrush polymers and their intracellular uptake in CT26 colon cancer cells. Furthermore, the bottlebrush macromolecular structure visibly enhanced the pharmacokinetics by reducing renal clearance and extending plasma half-lives. Real-time analysis of the biodistribution dynamics showed architecture-driven organ distribution and enhanced tumor accumulation. This work, therefore, introduces a robust, controlled synthesis route to bottlebrush polypeptides, overcoming limitations of current polymer-based nanomedicines and, in doing so, offers valuable insights into the influence of architecture on the in vivo performance of nanomedicines. 相似文献
68.
Gordana S. ?etkovi? Jasna M. ?anadanovi?-Brunet Sonja M. Djilas Vesna T. Tumbas Sini?a L. Markov Dragoljub D. Cvetkovi? 《International journal of molecular sciences》2007,8(10):1013-1027
The antioxidant activity of different Satureja montana L. subsp. kitaibelii extracts was tested by measuring their ability to scavenge reactive hydroxyl radical during the Fenton reaction, using ESR spectroscopy. Also, the influence of these extracts on lipid peroxyl radicals obtained during lipid peroxidation of: (I) sunflower oil (37 ºC, 3h) induced by 4,4′-azobis(4-cyanovaleric acid) (ACVA) and (II) liposomes induced by 2,2′-azobis(2- amidino-propane)dihydrochloride (AAPH) was studied. n-Butanol extract had the best antioxidant activity (100% at 0.5 mg/mL in Fenton reaction system; 89.21% at 5 mg/mL in system I; 83.38% at 5 mg/mL in system II). The antioxidant activities of the extracts significantly correlated with total phenolic content. The antimicrobial activity of Satureja montana L. subsp. kitaibelii extracts was investigated. Petroleum ether, chloroform and ethyl acetate extracts expressed a wide range of inhibiting activity against both grampositive and gram-negative bacteria. 相似文献
69.
Synthetic Indolactam V Analogues as Inhibitors of PAR2‐Induced Calcium Mobilization in Triple‐Negative Breast Cancer Cells
下载免费PDF全文
![点击此处可从《ChemMedChem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Jan Stein Dr. Sonja Stahn Dr. Jörg‐M. Neudörfl Julia Sperlich Prof. Dr. Hans‐Günther Schmalz Prof. Dr. Nicole Teusch 《ChemMedChem》2018,13(2):147-154
Human proteinase‐activated receptor 2 (PAR2), a transmembrane G‐protein‐coupled receptor (GPCR), is an attractive target for a novel anticancer therapy, as it plays a critical role in cell migration and invasion. Selective PAR2 inhibitors therefore have potential as anti‐metastatic drugs. Knowing that the natural product teleocidin A2 is able to inhibit PAR2 in tumor cells, the goal of the present study was to elaborate structure–activity relationships and to identify potent PAR2 inhibitors with lower activity against the adverse target, protein kinase C (PKC). For this purpose, an efficient gram‐scale total synthesis of indolactam V (i.e., the parent structure of all teleocidins) was developed, and a library of derivatives was prepared. Some compounds were indeed found to exhibit high potency as PAR2 inhibitors at low nanomolar concentrations with improved selectivity (relative to teleocidin A2). The pseudopeptidic fragment bridging the C3 and C4 positions of the indole core proved to be essential for target binding, whereas activity and target selectivity depends on the substituents at N1 or C7. This study revealed novel derivatives that show high efficacy in PAR2 antagonism combined with increased selectivity. 相似文献
70.
Although housing conditions were an integral part of the emergence of the Public Health movement, there has been relatively little research on the relationship between housing and health compared to that on social inequalities in general. This is surprising in view of the fact that one of the major links between social inequalities and health is adverse housing conditions. Findings from previous investigations in several countries of the presence of damp and mould in housing and symptoms in the occupants have indicated that the associations may well be causal. However, there have been no studies which have assessed the health of the residents before and after the elimination of dampness/mould. This paper describes a longitudinal study designed to evaluate the effects of an improved heating system on the symptoms of children living on a peripheral housing estate. The results suggested that the elimination of dampness/mould prevented a further deterioration in health rather than bringing about an improvement. The presence of other factors known to influence health status, such as financial difficulties and other housing problems, may have offset any benefits arising from the new heating system. The methodological issues that arose in conducting the study in an area of severe social disadvantage are described. It is suggested that the complexity of the interactions between bad housing and low income, should not detract attention from the need for intersectoral co‐operation to address the issue. 相似文献