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   394篇
  免费   10篇
  国内免费   1篇
电工技术   2篇
化学工业   113篇
金属工艺   9篇
机械仪表   8篇
建筑科学   9篇
能源动力   16篇
轻工业   35篇
水利工程   2篇
无线电   29篇
一般工业技术   49篇
冶金工业   18篇
原子能技术   10篇
自动化技术   105篇
  2024年   2篇
  2023年   3篇
  2022年   5篇
  2021年   28篇
  2020年   12篇
  2019年   13篇
  2018年   13篇
  2017年   7篇
  2016年   14篇
  2015年   13篇
  2014年   20篇
  2013年   29篇
  2012年   28篇
  2011年   41篇
  2010年   18篇
  2009年   26篇
  2008年   25篇
  2007年   21篇
  2006年   13篇
  2005年   11篇
  2004年   5篇
  2003年   6篇
  2002年   6篇
  2001年   6篇
  2000年   4篇
  1999年   4篇
  1997年   7篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1993年   3篇
  1992年   1篇
  1991年   3篇
  1989年   1篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1964年   1篇
排序方式: 共有405条查询结果,搜索用时 98 毫秒
21.
This work studies the heat influence in cutting tools considering the variation of the coating thickness and the heat flux. K10 and diamond tools substrate with TiN and Al2O3 coatings were used. The numerical methodology utilizes the ANSYS® CFX software. Boundary conditions and constant thermo physical properties of the solids involved in the numerical analysis are known. To validate the proposed methodology an experiment is used. The TiN and Al2O3 coatings did not show satisfying results during a continuous cutting process. It showed a slight reduction in the heat flux for the 10 (µm) TiN and Al2O3 coatings.  相似文献   
22.
In this paper an attempt is made to provide a proper formalization to the partial realization problem for discrete linear causal shift invariant 2-D systems. The approach falls into the class of 2-D Padé approximations; the results, however, are new, since the rational representation matches all the samples of a 2-D partial sequence. The realization algorithm, though characterized by a high complexity, exhibits a recursive structure and allows for a good computational economy.  相似文献   
23.
A growing body of evidence suggests that most adults exposed to potentially traumatic events are resilient. However, research on the factors that may promote or deter adult resilience has been limited. This study examined patterns of association between resilience and various sociocontextual factors. The authors used data from a random-digit-dial phone survey (N = 2,752) conducted in the New York City area after the September 11, 2001, terrorist attack. Resilience was defined as having 1 or 0 posttraumatic stress disorder symptoms and as being associated with low levels of depression and substance use. Multivariate analyses indicated that the prevalence of resilience was uniquely predicted by participant gender, age, race/ethnicity, education, level of trauma exposure, income change, social support, frequency of chronic disease, and recent and past life stressors. Implications for future research and intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
24.
The concept of superpeer has been introduced to improve the performance of popular P2P applications. A superpeer is a "powerful" node that acts as a server for a set of clients, and as an equal with respect to other superpeers. By exploiting heterogeneity, the superpeer paradigm can lead to improved efficiency, without compromising the decentralized nature of P2P networks. The main issues in constructing superpeer-based overlays are the selection of superpeers and the association between superpeers and clients. Generally, superpeers are either run voluntarily (without an explicit selection process), or chosen among the "best" nodes in the network, for example those with the most abundant resources, such as bandwidth or storage. In several contexts, however, shared resources are not the only factor; latency between clients and superpeers may play an important role, for example in online games and IP-Telephony applications. This paper presents SG-2, a novel protocol for building and maintaining proximity-aware superpeer topologies. SG-2 uses a gossip-based protocol to spread messages to nearby nodes and a biology-inspired task allocation mechanism to promote the "best" nodes to superpeer status. The paper includes extensive simulation experiments to prove the efficiency, scalability and robustness of SG-2.  相似文献   
25.
Semantic web services are gaining more attention as an important element of the emerging semantic web. Therefore, testing semantic web services is becoming a key concern as an essential quality assurance measure. The objective of this systematic literature review is to summarize the current state of the art of functional testing of semantic web services by providing answers to a set of research questions. The review follows a predefined procedure that involves automatically searching 5 well-known digital libraries. After applying the selection criteria to the results, a total of 34 studies were identified as relevant. Required information was extracted from the studies and summarized. Our systematic literature review identified some approaches available for deriving test cases from the specifications of semantic web services. However, many of the approaches are either not validated or the validation done lacks credibility. We believe that a substantial amount of work remains to be done to improve the current state of research in the area of testing semantic web services.  相似文献   
26.
OVERVIEW: Over the last decade, the utility of immobilized microfluidic enzyme reactors (IMERs) has been demonstrated in a wide variety of fields, including medical diagnostics and therapy, biosensors, organic synthesis, drug discovery and many other applications. Of particular interest to the pharmaceutical industry is the potential for high throughput experimentation afforded by these systems, with a view to combinatorial synthesis for drug discovery applications. This article will focus on the current state of IMER systems, including immobilization techniques and microchannel flow generation, with a particular emphasis on applications and future prospects in view of likely directions and market potential of this field. IMPACT: The numerous advantages of attaching enzymes to a solid support, such as reuse of a single batch of enzyme, improved stability and durability, the ability to stop the reaction rapidly by removing the product from the reaction solution and the absence of enzyme contamination of the product are some of the attractive features of such systems. There are, however, a number of issues requiring careful consideration when developing such microsystems, including, but not limited to, surface modifications and exact control of fluid behaviour in microchannels, detection limitations, increased integration, and the reusability of the chips. APPLICATIONS: IMERs have received wide, including commercial, application as diagnostic tools for point‐of‐care applications, and, increasingly, as analytical tools in early drug development. Furthermore, peptide mapping and proteomics have employed IMER systems extensively over the past decade and growth in these areas continues. Copyright © 2011 Society of Chemical Industry  相似文献   
27.
Autoclave processing is commonly used nowadays for dewaxing in the investment casting process. However, since the use of microwave is steadily growing in industrial processes and the wax interacts with the electromagnetic energy of the microwaves, the present work studies the possibility of carrying out dewaxing via microwave. The wax (mineral wax, vegetable resin, low molecular-weight polymer and anti-oxidant) used in this work was prepared by melting in an oven equipped with a mineral oil bath. The chemical and structural stability of the wax were monitored throughout 12 simulated dewaxing cycles, via various analyses, namely, volumetric expansion, hardness, Fourier transform infrared spectroscopy, ultraviolet–visible spectrophotometry, differential scanning calorimetry and viscosity. The results showed that microwave dewaxing is viable, significantly decreasing the incorporation of dirt and water, which is inevitable in the autoclave dewaxing process.  相似文献   
28.
引言   ST最新推出的M50FW040固件集线器,采用了被称作‘低引脚数接口规范’或LPC的新主板互连协议。LPC总线是主板芯片组和单板外设功能之间的高速接口。……  相似文献   
29.
The paper aims to investigate how innovations cluster in different technological systems (TSs) when their “techno‐economic”, rather than “territorial” space, is considered. Innovation clusters of economic sectors are identified by referring to the innovation “potential” represented by their R&D expenditure and by applying social network analysis to the intersectoral R&D flows matrices of 15 OECD countries in the mid‐1990s. Different clusterization models are first tested in order to detect the way sectors group on the basis of the embodied R&D flows they exchange. Actual clusters are then mapped in the different TSs by looking for intersectoral relationships which can be qualified to constitute “reduced TSs” (ReTSs). In all the 15 TSs investigated the techno‐economic space appears organized in hierarchies, along which its constitutive sectors grouped into clusters with different density and composition. Once ReTSs are looked for, the 15 TSs display highly heterogeneous structures, but with some interesting similarity on the basis of which different clusters of TSs can be identified in turn.  相似文献   
30.
Steven–Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe adverse drug reactions, characterized by extensive epidermal detachment and erosions of mucous membrane. SJS/TEN is one of the most serious adverse reactions to Nevirapine (NVP) treatment, commonly used in developing countries as first-line treatment of human immunodeficiency virus infection. In the last years TRAF3IP2 gene variants had been described as associated with susceptibility to several diseases such as psoriasis and psoriatic arthritis. We hypothesized that this gene, involved in immune response and in NF-κB activation, could also be implicated in the SJS/TEN susceptibility. We performed a full resequencing of TRAF3IP2 gene in a population of patients treated with NVP. Twenty-seven patients with NVP-induced SJS/TEN and 78 controls, all from Mozambique, were enrolled. We identified eight exonic and three intronic already described variants. The case/control association analysis highlighted an association between the rs76228616 SNP in exon 2 and the SJS/TEN susceptibility. In particular, the variant allele (C) resulted significantly associated with a higher risk to develop SJS/TEN (p = 0.012 and OR = 3.65 (95% CI 1.33–10.01)). A multivariate analysis by logistic regression confirmed its significant contribution (p = 0.027, OR = 4.39 (95% CI 1.19–16.23)). In conclusion, our study suggests that a variant in TRAF3IP2 gene could be involved in susceptibility to SJS/TEN.  相似文献   
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