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   61873篇
  免费   5917篇
  国内免费   3172篇
电工技术   4470篇
技术理论   9篇
综合类   6353篇
化学工业   3658篇
金属工艺   955篇
机械仪表   2730篇
建筑科学   8874篇
矿业工程   4146篇
能源动力   1818篇
轻工业   7978篇
水利工程   4133篇
石油天然气   5317篇
武器工业   1161篇
无线电   3167篇
一般工业技术   4455篇
冶金工业   1885篇
原子能技术   1214篇
自动化技术   8639篇
  2024年   346篇
  2023年   914篇
  2022年   1826篇
  2021年   2250篇
  2020年   2359篇
  2019年   1794篇
  2018年   1797篇
  2017年   1987篇
  2016年   2447篇
  2015年   2514篇
  2014年   4811篇
  2013年   4037篇
  2012年   5264篇
  2011年   5060篇
  2010年   3759篇
  2009年   3719篇
  2008年   3414篇
  2007年   4071篇
  2006年   3562篇
  2005年   2990篇
  2004年   2355篇
  2003年   2045篇
  2002年   1478篇
  2001年   1228篇
  2000年   951篇
  1999年   779篇
  1998年   559篇
  1997年   529篇
  1996年   403篇
  1995年   346篇
  1994年   272篇
  1993年   225篇
  1992年   138篇
  1991年   125篇
  1990年   84篇
  1989年   104篇
  1988年   62篇
  1987年   38篇
  1986年   36篇
  1985年   36篇
  1984年   37篇
  1983年   38篇
  1982年   18篇
  1981年   14篇
  1979年   13篇
  1978年   11篇
  1977年   9篇
  1963年   7篇
  1959年   13篇
  1956年   7篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
We present a digital laboratory safety training platform called AALTOLAB which we have developed to address the need for more flexible and engaging ways to teach laboratory safety for chemical engineers. AALTOLAB consists of an interactive, web-based 360° virtual laboratory, integrated with a Moodle-based digital exam with automatic assessment. The modular platform offers different modules from general comprehensive laboratory training to more specialised modules. Students and staff can freely navigate in the laboratory rooms at any time and interact with different action points including interactive videos, slideshows, and minigames. Our technical solution allows teachers even with limited technological skills to easily modify the training materials in real time. The relationship of students’ learning experiences and level of learning is also discussed. We believe that our safety training concept facilitates deep learning and students’ engagement, thus improving safety culture in our laboratories.  相似文献   
82.
超细粉生产技术的新发展   总被引:7,自引:0,他引:7  
冯改山 《硅酸盐通报》1993,12(2):43-47,71
  相似文献   
83.
以推动人类文明进步发展的观念为先导,以详实的地质学、岩石学、石文化史料为切入点,介绍了我国观赏石文化的起源、发展及现状;阐述了赏石审美的本质、形式、石体标准、传统性、现代性等理论要点及其以小见大、以丑为美的审美理念。对赏石修身养性、以石陶情及赏石文化与道教情结的学术价值进行了评述;对从古至今的中华文化名人为赏石理论的创立、鉴赏、收藏和发展作出的不可磨灭的历史贡献进行了评价。  相似文献   
84.
列举了业主规定的压型钢板的涂装配套及膜厚要求,介绍了锌加的涂装工艺、安全与环保、质量检验。  相似文献   
85.
In this paper we introduce a multi-method multiple criteria approach for evaluating the performance of organizations. Performance analysis may include both strategic and operational performance, as well as financial and other less tangible factors. This paper introduces the use of Fuzzy C-Means and TOPSIS for organizational performance evaluation purposes. Using real company data and balanced scorecard accounting and performance dimensions the methodology is applied and evaluated. The predictive abilities of the technique from an organizational performance evaluation approach are evaluated using this data. One of the results from the illustrative application is that economic performance evaluation is not the best predictor of overall viability of some organizations, especially e-commerce based organizations.  相似文献   
86.
Information systems (IS) facilitate organisations to increase responsiveness and reduce the costs of their supply chain. This paper seeks to make a contribution through exploring and visualising knowledge mapping from the perspective of IS investment evaluation. The evaluation of IS is regarded as a challenging and complex process, which becomes even more difficult with the increased complexity of IS. The intricacy of IS evaluation, however, is due to numerous interrelated factors (e.g. costs, benefits and risks) that have human or organisational dimensions. With this in mind, there appears to be an increasing need to assess investment decision-making processes, to better understand the often far-reaching implications associated with technology adoption and interrelated knowledge components (KC). Through the identification and extrapolation of key learning issues from the literature and empirical findings, organisations can better improve their business processes and thereby their effectiveness and efficiency, while preventing others from making costly oversights that may not necessarily be only financial. In seeking to enlighten the often obscure evaluation of IS investments, this paper attempts to inductively emphasise the dissemination of knowledge and learning through the application of a fuzzy Expert System (ES) based knowledge mapping technique (i.e. Fuzzy Cognitive Map [FCM]). The rationale for exploring knowledge and IS investment evaluation is that a knowledge map will materialise for others to exploit during their specific technology evaluation. This is realised through conceptualising the explicit and tacit investment drivers. Among the several findings drawn from this research, the key resulting knowledge mapping through FCM demonstrated the complex, multifaceted and emergent behaviour of causal relationships within the knowledge area. The principal relationships and knowledge within IS investment evaluation are illustrated as being determined by a blend of managerial and user perspectives.  相似文献   
87.
Senior managers can have a strong influence on organisational safety. But little is known about which of their personal attributes support their impact on safety. In this paper, we introduce the concept of ‘safety intelligence’ as related to senior managers' ability to develop and enact safety policies and explore possible characteristics related to it in two studies. Study 1 (N = 76) involved direct reports to chief executive officers (CEOs) of European air traffic management (ATM) organisations, who completed a short questionnaire asking about characteristics and behaviours that are ideal for a CEO's influence on safety. Study 2 involved senior ATM managers (N = 9) in various positions in interviews concerning their day-to-day work on safety. Both studies indicated six attributes of senior managers as relevant for their safety intelligence, particularly, social competence and safety knowledge, followed by motivation, problem-solving, personality and interpersonal leadership skills. These results have recently been applied in guidance for safety management practices in a White Paper published by EUROCONTROL.  相似文献   
88.
In Winkel (2001) a generalization of Bernstein polynomials and Bézier curves based on umbral calculus has been introduced. In the present paper we describe new geometric and algorithmic properties of this generalization including: (1) families of polynomials introduced by Stancu (1968) and Goldman (1985), i.e., families that include both Bernstein and Lagrange polynomial, are generalized in a new way, (2) a generalized de Casteljau algorithm is discussed, (3) an efficient evaluation of generalized Bézier curves through a linear transformation of the control polygon is described, (4) a simple criterion for endpoint tangentiality is established.  相似文献   
89.
针对综合交通网络评价指标权重及属性值具有主观性和随机性的特点,提出了基于模拟运算的布局规划方案排序选优的群体随机决策方法.仿真生成满足集结的多个专家对指标重要性偏好排序统计分布的权重,同时考虑交通需求的不确定性对指标值的影响,结合客观熵权计算方案的综合评价值,由多次模拟得到的排序优势度确定方案的优劣差异.根据设计的仿真流程通过算例说明了方法应用的有效性,评价中考虑了主客观因素及随机性特征,可以为网络布局提供科学决策依据.  相似文献   
90.
针对云服务业务流程管理的特点, 给出了云服务的组合实现框架; 依据随机Petri网的建模理论, 探讨了组合云服务流程网模型的细粒度建模方法; 根据动态多变的用户需求, 设计了二维多层次的云服务组合可靠性动态评估框架, 并给出了马尔可夫过程和等值约简的两种可靠性计算方法。应用示例分析结果表明, 该方法具有较好的动态适应性和灵活性, 能有效满足云服务的可靠性评估需求。  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