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   1948篇
  免费   89篇
  国内免费   52篇
电工技术   57篇
综合类   319篇
化学工业   348篇
金属工艺   27篇
机械仪表   56篇
建筑科学   303篇
矿业工程   63篇
能源动力   104篇
轻工业   232篇
水利工程   128篇
石油天然气   64篇
武器工业   2篇
无线电   72篇
一般工业技术   95篇
冶金工业   96篇
原子能技术   4篇
自动化技术   119篇
  2024年   4篇
  2023年   10篇
  2022年   27篇
  2021年   39篇
  2020年   57篇
  2019年   45篇
  2018年   35篇
  2017年   37篇
  2016年   58篇
  2015年   42篇
  2014年   132篇
  2013年   101篇
  2012年   152篇
  2011年   146篇
  2010年   130篇
  2009年   107篇
  2008年   103篇
  2007年   143篇
  2006年   148篇
  2005年   127篇
  2004年   97篇
  2003年   75篇
  2002年   73篇
  2001年   39篇
  2000年   35篇
  1999年   32篇
  1998年   20篇
  1997年   7篇
  1996年   7篇
  1995年   4篇
  1994年   6篇
  1993年   7篇
  1992年   4篇
  1991年   4篇
  1990年   3篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1986年   4篇
  1985年   7篇
  1984年   6篇
  1983年   5篇
  1982年   1篇
  1963年   1篇
排序方式: 共有2089条查询结果,搜索用时 15 毫秒
21.
A variety of wound healing platforms have been proposed to alleviate the hypoxic condition and/or to modulate the immune responses for the treatment of chronic wounds in diabetes. However, these platforms with the passive diffusion of therapeutic agents through the blood clot result in the relatively low delivery efficiency into the deep wound site. Here, a microalgae-based biohybrid microrobot for accelerated diabetic wound healing is developed. The biohybrid microrobot autonomously moves at velocity of 33.3 µm s−1 and generates oxygen for the alleviation of hypoxic condition. In addition, the microrobot efficiently bound with inflammatory chemokines of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) for modulating the immune responses. The enhanced penetration of microrobot is corroborated by measuring fibrin clots in biomimetic wound using microfluidic devices and the enhanced retention of microrobot is confirmed in the real wounded mouse skin tissue. After deposition on the chronic wound in diabetic mice without wound dressing, the wounds treated with microrobots are completely healed after 9 days with the significant decrease of inflammatory cytokines below 31% of the control level and the upregulated angiogenesis above 20 times of CD31+ cells. These results confirm the feasibility of microrobots as a next-generation platform for diabetic wound healing.  相似文献   
22.
Strategy, networks and systems in the global translation services market   总被引:1,自引:0,他引:1  
The globalisation of markets has led to an increased demand for language translation services that support and enable communication between economic partners. For example, technical documents, software systems, business documents and web sites all need to be translated into multiple languages for individual national markets, and the information that they contain changes periodically. This paper sets out a theoretical framework that describes the architectures of business processes within and between separate firms that are used to support the delivery and management of services. This is done by coordinating the fit between externally generated problem complexity, from customers, and the internally generated complexity of different potential network configuration solutions. The theoretical framework is an architecture of how complexity is generated and managed at the different structural levels and across the different processual stages of an industry. A case study of thebigword, a major international translation services company, illustrates how the framework is applied in practice. The case study analyses the implementation of an electronic market platform which enables the coordination of the different stakeholders involved in the translation services market. These stakeholders include translators, translation services companies and their clients in a global business network.  相似文献   
23.
数字绘画作为一种新兴的艺术形式。在艺术创作过程中,从单纯地模仿走向利用电脑程序在电脑中创作或自动生成图像,达到了一定的艺术效果。同时,它也在不知不觉中或多或少地影响了传统的插画艺术。这两种绘画方式具有各自独特的个性及美感,我们把更多的目光投向了这两种技术手段的相通性。探讨在这两者间相互影响的过程中,在超越这些"感觉材料"之上、之外,是否存在着一个共同体,构成了不同的艺术手段之间的作品。  相似文献   
24.
The United Parcel Service (UPS)–Motorola case study revolves around two major areas of information technology (IT) management: IT as a competitive tool and global outsourcing of IT projects. It provides an opportunity to become familiar with the decisions and actions taken by UPS to assure their competitive advantage in the turbulent courier services industry. In the IT outsourcing area, the case addresses managerial and technical issues associated with outsourcing IT projects across the global community. The case presents the specific factors that made this outsourcing project successful and discusses the development of the outsourcing relationships between UPS and Motorola (Israel), from initial negotiations to the creation of a strategic alliance between the two companies. A major point in this case is the gradual development of trust between the two sides, trust that led the two firms from being committed to a contract to becoming strategic partners.  相似文献   
25.
西安黑河金盆水库季节性热分层的水质响应特征   总被引:17,自引:1,他引:16  
以西安市金盆水库为对象,通过对水温、水化学及水生生物因子的连续监测,初步探明其动态水体分层过程与季节性水质迁移分布的内在相关性.研究表明:水库于每年3—12月间形成并保持热分层状态,水温梯度的稳定存在有效限制了垂向水层间氧的传质交换,加速库底向厌氧状态过渡,滞水层溶解氧(DO)平均浓度随时间呈明显线性衰减趋势,水层呼吸速率高达0.0356~0.0372mg/(L·d)(O2);缺氧/厌氧环境下,沉积物中N、P、Fe等大量释放并向上覆水扩散,底层水质污染加剧.同温混合期后(1—2月),分层结构破坏,全库处于好氧(DO大于8mg/L)、微碱性(pH为7.1~7.3)状态,垂向水质分层异质特征消失.监测期间,水库湖泊区稳态叶绿素a含量(基于Lois Elle稳态假设前提)随混合深度增大而降低,两者存在显著指数负相关.热分层效应的稳定存在是加速金盆水库富营养化进程的重要因素;而其周期性结构失稳所带来的水质突发性污染风险将伴随水库运行时间的延长而上升.  相似文献   
26.
通过文献资料调研、问卷调查、专家访谈、案例分析、逻辑归纳等方法,简要综述国内外夜间定向、国内普通高校夜间定向训练现状,研究分析我国普通高校开展的夜间定向训练优势及制约因素,最后结合教学实践提出若干建议。  相似文献   
27.
区域生长法被广泛应用于对特定目标的选取,但其生长速度缓慢的特点又限制了其在某些领域的应用.为此,提出一种基于相似点区段负责制的像素点进出堆栈管理方法,有效的提高了区域生长的效率.在此基础上,结合链码法边界跟踪对生长过程中区域内部出现的孔洞实现区域补偿,建立了针对链状藻细胞分析统计的有效应用系统.  相似文献   
28.
This paper analyzes the Russian software industry in the context of trade in information technology services. We assess Russia's underlying sources of competitive edge in software, such as its scientific establishments, education system, diaspora and low costs, and identify the institutional impediments to growth. A survey reveals that foreign outsourcing contracts, a high value-added niche and high education levels characterize Russia's small, privately held software firms. A comparison with the Indian software industry underscores the structural differences in outsourcing relationships developed by the two countries and emphasizes that national advantages are complex amalgamations of many factors and need to be overtly marketed. Beyond the resources that give comparative and competitive advantage to a transitioning economy, a critical role is played by powerful industry organizations and by non-market state institutions that can level the economic field and inject credibility into market structures.  相似文献   
29.
Pakistan's bedwear industry contributes significantly to Pakistan's industry in general and to its textile industrial output and exports in particular. The exports of bedwear have increased steadily. However, its key basis of competitive advantage has been low cost. After greater liberalization from 2005 onwards and due to tariffication of quotas, the bedwear industry will not only have to scale higher tariff walls but will be more exposed to the threat of anti-dumping duties as it relies primarily on low prices to penetrate the export markets. To enhance its competitiveness, it will have to combine better quality with low costs and quick response. Research in quality management in Pakistan's bedwear industry was, therefore, undertaken. A postal self-completion questionnaire was mailed to 38 members of Pakistan Bedwear Manufacturers' and Exporters' Association (PBMEA). The response rate was almost 79%. It was found that this industrial segment was in various stages of development. This study demonstrates both the effectiveness and the limits of quality assurance in improving the levels of quality which remain a moving target in a dynamic liberalizing international trade environment that is more competitive since 2005. The bedwear industry, therefore, needs to graduate to advanced practices in quality management in order to remain competitive in rapidly changing times.  相似文献   
30.
介绍了N330—17.75/540/540型中间再热式大功率汽轮机机组中压缸启动的优点和方法及注意事项。对于调峰机组。旁路容量条件、控制条件具备时。建议采用中压缸启动。  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