首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   232篇
  免费   19篇
  国内免费   1篇
电工技术   6篇
化学工业   74篇
金属工艺   6篇
机械仪表   3篇
建筑科学   4篇
能源动力   16篇
轻工业   59篇
石油天然气   1篇
无线电   12篇
一般工业技术   38篇
冶金工业   18篇
自动化技术   15篇
  2024年   1篇
  2023年   2篇
  2022年   16篇
  2021年   20篇
  2020年   15篇
  2019年   7篇
  2018年   6篇
  2017年   15篇
  2016年   18篇
  2015年   10篇
  2014年   10篇
  2013年   11篇
  2012年   12篇
  2011年   14篇
  2010年   17篇
  2009年   8篇
  2008年   15篇
  2007年   7篇
  2006年   7篇
  2005年   4篇
  2004年   4篇
  2003年   7篇
  2002年   4篇
  2001年   4篇
  2000年   5篇
  1999年   1篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1987年   1篇
  1978年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有252条查询结果,搜索用时 31 毫秒
241.
This paper presents a quality of experience (QoE) conceptual model to the context of unified communications (UC) through summary, classification, and discussion of multiple influence factors (IFs) and dimensions affecting it. A deep and comprehensive understanding of the IFs and their impact on QoE for a given service is an essential precondition for successful QoE management with the overall goal of prominently optimizing end‐user QoE, while making efficient use of network resources and maintaining a satisfied user base. The proposed conceptual model was used to conduct a qualitative meta‐analytical review of selected papers. The results of the qualitative review include various IFs, QoE dimensions, and key findings in the form of research recommendations for QoE in the context of UC.  相似文献   
242.
In view of the unsatisfactory treatment of cognitive disorders, in particular Alzheimer’s disease (AD), the aim of this review was to perform a computer-aided analysis of the state of the art that will help in the search for innovative polypharmacology-based therapeutic approaches to fight against AD. Apart from 20-year unrenewed cholinesterase- or NMDA-based AD therapy, the hope of effectively treating Alzheimer’s disease has been placed on serotonin 5-HT6 receptor (5-HT6R), due to its proven, both for agonists and antagonists, beneficial procognitive effects in animal models; however, research into this treatment has so far not been successfully translated to human patients. Recent lines of evidence strongly emphasize the role of kinases, in particular microtubule affinity-regulating kinase 4 (MARK4), Rho-associated coiled-coil-containing protein kinase I/II (ROCKI/II) and cyclin-dependent kinase 5 (CDK5) in the etiology of AD, pointing to the therapeutic potential of their inhibitors not only against the symptoms, but also the causes of this disease. Thus, finding a drug that acts simultaneously on both 5-HT6R and one of those kinases will provide a potential breakthrough in AD treatment. The pharmacophore- and docking-based comprehensive literature analysis performed herein serves to answer the question of whether the design of these kind of dual agents is possible, and the conclusions turned out to be highly promising.  相似文献   
243.
On a daily basis, people are exposed to a multitude of health-hazardous airborne particulate matter with notable deposition in the fragile alveolar region of the lungs. Hence, there is a great need for identification and prediction of material-associated diseases, currently hindered due to the lack of in-depth understanding of causal relationships, in particular between acute exposures and chronic symptoms. By applying advanced microscopies and omics to in vitro and in vivo systems, together with in silico molecular modeling, it is determined herein that the long-lasting response to a single exposure can originate from the interplay between the newly discovered nanomaterial quarantining and nanomaterial cycling between different lung cell types. This new insight finally allows prediction of the spectrum of lung inflammation associated with materials of interest using only in vitro measurements and in silico modeling, potentially relating outcomes to material properties for a large number of materials, and thus boosting safe-by-design-based material development. Because of its profound implications for animal-free predictive toxicology, this work paves the way to a more efficient and hazard-free introduction of numerous new advanced materials into our lives.  相似文献   
244.
Panagiotis Isigonis  Antreas Afantitis  Dalila Antunes  Alena Bartonova  Ali Beitollahi  Nils Bohmer  Evert Bouman  Qasim Chaudhry  Mihaela Roxana Cimpan  Emil Cimpan  Shareen Doak  Damien Dupin  Doreen Fedrigo  Valrie Fessard  Maciej Gromelski  Arno C. Gutleb  Sabina Halappanavar  Peter Hoet  Nina Jeliazkova  Stphane Jomini  Sabine Lindner  Igor Linkov  Eleonora Marta Longhin  Iseult Lynch  Ineke Malsch  Antonio Marcomini  Espen Mariussen  Jesus M. de la Fuente  Georgia Melagraki  Finbarr Murphy  Michael Neaves  Rolf Packroff  Stefan Pfuhler  Tomasz Puzyn  Qamar Rahman  Elise Rundn Pran  Elena Semenzin  Tommaso Serchi  Christoph Steinbach  Benjamin Trump  Ivana Vinkovi&#x; Vr ek  David Warheit  Mark R. Wiesner  Egon Willighagen  Maria Dusinska 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(36)
Nanotechnologies have reached maturity and market penetration that require nano‐specific changes in legislation and harmonization among legislation domains, such as the amendments to REACH for nanomaterials (NMs) which came into force in 2020. Thus, an assessment of the components and regulatory boundaries of NMs risk governance is timely, alongside related methods and tools, as part of the global efforts to optimise nanosafety and integrate it into product design processes, via Safe(r)‐by‐Design (SbD) concepts. This paper provides an overview of the state‐of‐the‐art regarding risk governance of NMs and lays out the theoretical basis for the development and implementation of an effective, trustworthy and transparent risk governance framework for NMs. The proposed framework enables continuous integration of the evolving state of the science, leverages best practice from contiguous disciplines and facilitates responsive re‐thinking of nanosafety governance to meet future needs. To achieve and operationalise such framework, a science‐based Risk Governance Council (RGC) for NMs is being developed. The framework will provide a toolkit for independent NMs' risk governance and integrates needs and views of stakeholders. An extension of this framework to relevant advanced materials and emerging technologies is also envisaged, in view of future foundations of risk research in Europe and globally.  相似文献   
245.
In this study we report for the first time the localization of a photoreceptor pigment in the cilia of the colored heterotrich ciliates Blepharisma japonicum red and blue form, Fabrea salina, and Stentor coeruleus, as result of a confocal microscopy investigation. Optical sectioning confocal microscopy has been used for studying the spatial distribution of the pigment in the cell body, surprisingly showing that, besides its expected presence in the cortical region immediately below the cell membrane, it is located in the cilia too. In order to ascertain possible differences in the pigment fluorescence properties along the cell body, we have measured emission spectra from different parts of it (anterior, posterior, and cilia). Our results clearly indicate that in all cases the spectra are the same, within experimental errors. Finally, we have evaluated the pigment relative fluorescence efficiency of these ciliates. In an ordered scale from lower to greater efficiency, we have S. coeruleus, B. japonicum blue, B. japonicum red, and F. salina. The possible implications of our findings for the process of photosensory transduction are discussed.  相似文献   
246.
Nylon 6,6 electrospun nanofibrous membranes interleaved in “high performance” Carbon Fiber Reinforced Polymer (CFRP) laminates have been proposed as a means to provide a high threshold value to delamination on structural sites where composites are more prone to develop such failure. A model, highly crosslinked, thus inherently brittle, epoxy matrix was selected for its high Young's modulus and glass transition temperature exceeding 250°C. The influence of the Nylon 6,6 nanofibers on the curing behavior of the matrix and on the thermal and dynamic mechanical properties of the cured resin was investigated. These properties were related to the features of the epoxy resin and of the resin impregnated nanofibrous mat. Finally, the delamination behavior of the composite laminates interleaved with Nylon interleaves with different thicknesses was studied through Mode I delamination tests on Double Cantilever Beam (DCB) samples. The results show that the initial Mode I fracture toughness was increased up to about 50% by the presence of the thin mat interleaf. POLYM. COMPOS., 36:1303–1313, 2015. © 2014 Society of Plastics Engineers  相似文献   
247.
3-Iodothyronamine (T(1)AM) is a novel relative of thyroid hormone that plays a role in critical body regulatory processes such as glucose metabolism, thermal regulation, and heart beating. This paper was aimed at characterizing time dynamics of T(1)AM and its catabolite 3-iodothyroacetic acid (TA(1)) in different biological scales with linear time-invariant models. Culture medium samples coming from culture of H9c2 murine cells and perfusion liquid samples from perfused rat heart were collected after the injection of a T(1)AM bolus. T(1)AM and TA(1) concentrations in the samples were assayed with high-performance liquid chromatography coupled to tandem mass spectrometry. Kinetic constants relative to T(1)AM transport and conversion were estimated with weighted least-squares method. We found that these constants can be related with an allometric power law depending on mass, with a negative exponent of -0.27 ± 0.19, implying that the velocity of conversion and internalization of T(1)AM decreases with increasing of system mass.  相似文献   
248.
Wine proteins play an important role in different characteristics of wine (e.g., aroma and body, foaming in sparkling wines). They can also cause a number of technological problems during vinification and may be responsible for the appearance of turbidity in bottled wine. These important features of proteins in wine have made necessary the development of new and fast analytical methods that can provide deeper knowledge about these biopolymers. However, separation and characterization of wine proteins is difficult and time-consuming mainly due to their low concentration and large number of interfering compounds. Besides, long sample preparation protocols can bring about protein decomposition. This paper proposes a new and fast method for carrying out the analysis of the protein fraction of wines. The procedure consists of direct treatment of wine using a centrifugal filter device (CFD), denaturation of the proteinaceous fraction with sodium dodecyl sulfate (SDS) and 2-mercaptoethanol, and subsequent CGE analysis of SDS-proteins. Results on the molecular weight (Mw) and relative quantity of proteins of wines are attained in about 1 h with this procedure. The method is applied to analyze different wines from Canary Islands. To our knowledge, this is the first report of separation of wine proteins according to their Mw by CGE.  相似文献   
249.
250.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号