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   88880篇
  免费   7360篇
  国内免费   3189篇
电工技术   15861篇
技术理论   18篇
综合类   5995篇
化学工业   9470篇
金属工艺   2838篇
机械仪表   3454篇
建筑科学   11643篇
矿业工程   2456篇
能源动力   14331篇
轻工业   2355篇
水利工程   1904篇
石油天然气   2349篇
武器工业   660篇
无线电   6335篇
一般工业技术   8770篇
冶金工业   4013篇
原子能技术   1319篇
自动化技术   5658篇
  2025年   964篇
  2024年   3048篇
  2023年   2682篇
  2022年   3341篇
  2021年   3472篇
  2020年   3749篇
  2019年   3332篇
  2018年   2666篇
  2017年   3078篇
  2016年   3514篇
  2015年   3306篇
  2014年   5755篇
  2013年   5329篇
  2012年   6021篇
  2011年   6586篇
  2010年   5133篇
  2009年   5105篇
  2008年   4554篇
  2007年   4979篇
  2006年   3965篇
  2005年   3050篇
  2004年   2508篇
  2003年   2166篇
  2002年   1919篇
  2001年   1664篇
  2000年   1400篇
  1999年   1113篇
  1998年   893篇
  1997年   710篇
  1996年   647篇
  1995年   465篇
  1994年   418篇
  1993年   336篇
  1992年   247篇
  1991年   228篇
  1990年   188篇
  1989年   148篇
  1988年   130篇
  1987年   96篇
  1986年   66篇
  1985年   96篇
  1984年   82篇
  1983年   52篇
  1982年   71篇
  1981年   33篇
  1980年   42篇
  1979年   25篇
  1978年   13篇
  1977年   11篇
  1951年   12篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
钢铁制造流程的能量流行为和能量流网络问题   总被引:1,自引:0,他引:1  
为应对全球气候变化,钢铁工业在下一步技术转型中,应高度重视钢铁制造流程的能量流和能量流网络问题。本文从充分发挥钢厂三个功能的视角,阐述了钢铁制造流程中铁素物质流和碳素能量流的行为规律,提出了应注重与铁素物质流相关的碳素能量流的输入/输出特点和能量流网络构建以及相应的信息化集成调控的观点,剖析了钢铁工业节能减排的潜力,指出了提高钢厂综合竞争力和多方位服务于可持续发展的可能性,探讨了相关理论的建立、技术开发和工程化实施的策略等。  相似文献   
82.
83.
In 2007, the UK Government announced an ambitious zero-carbon target for all new housing in England. This paper shows how the definition and its associated policies emerged from discourses of environmental policy innovation; how the problem subsequently became framed as one of mainstreaming, consequent upon the apparent success of experimental schemes and defined in more detail through the interaction between pressure group politics and the technical analyses that accompanied the government's consultation exercises. Finally, it shows how regional and local variations in housing and property markets are likely to influence the ease of zero carbon development. The analysis uses concepts drawn from both the science and technology literature and the literature on policy implementation.  相似文献   
84.
This paper reviews existing case studies and methods for calibrating whole building energy models to measured data. This research describes a systematic, evidence-based methodology for the calibration of these models. Under this methodology, parameter values in the final calibrated model reference the source of information used to make changes to the initial model. Thus, the final model is based solely on evidence. Version control software stores a complete record of the calibration process, and the evidence on which the final model is based. Future users can review the changes made throughout the calibration process along with the supporting evidence. In addition to the evidence-based methodology, this paper also describes a new zoning process that represents the real building more closely than the typical core and four perimeter zone approach. Though the methodology is intended to apply to detailed calibration studies with high resolution measured data, the primary aspects of the methodology (evidence-based approach, version control, and zone-typing) are independent of the available measured data.  相似文献   
85.
Sungwook Kim 《ETRI Journal》2011,33(3):407-414
In an effort to reduce energy consumption, research into adaptive power management in real‐time systems has become widespread. In this paper, a novel dynamic voltage scaling scheme is proposed for multiprocessor systems. Based on the concept of the Nash bargaining solution, a processor's clock speed and supply voltage are dynamically adjusted to satisfy these conflicting performance metrics. In addition, the proposed algorithm is implemented to react adaptively to the current system conditions by using an adaptive online approach. Simulation results clearly indicate that the superior performance of the proposed scheme can strike the appropriate performance balance between contradictory requirements.  相似文献   
86.
《国际生产研究杂志》2012,50(17):4793-4805
The purpose of this paper is to investigate the customer satisfaction of power users using the Analytic Hierarchy Process (AHP) method. The objective is to safeguard the interests of electricity consumers and to increase the profitability of the energy distributer. Compared with previous work based on customer questionnaires describing the level of satisfaction, and where the solution is judged to be random due to the low significance of the studied sample, this paper develops a novel strategy. It is based on a global and transparent process regarding the reliability and economic criteria associated with alternatives, highlighting technical and organisational measures taken by the enterprise. The importance of reliability and economic criteria to the alternatives is processed using reliability indices analysis and cost benefit analysis methods. To analyse the customer's reactions to the decisions taken by the system's manager, and to validate the obtained results using the AHP method, we introduce economic criteria often used in the case of an uncertain future. The obtained results indicate the advantage of investment to improve customer satisfaction and enterprise profitability. It is also shown that reliability criteria are significant in the performance of a business and are an important asset for the justification of new projects.  相似文献   
87.
薛祖源 《化工设计》2010,20(3):3-10,40
介绍气候变化的危害原因和我国能源利用效率与发达国家的差距,提出推进碳减排工作及发展低碳经济,以实现我国承诺的2020年减排指标的设想。  相似文献   
88.
地热能的开发应用在邯郸市正处在发展期。对近几年邯郸市开发的地热井调查,发现地热水矿化度极高且含有大量氯化物、硫酸盐等物质,地热废水绝大部分没有经过任何处理直接外排,对周围生态环境和工农业生产造成了很大危害。针对排放水水质、水量的不同特点,介绍了相应的处理方法。值得注意的是这种高矿化度、高水温的地热排放水在国家排放标准中没有给予指标限制,这些排放水的危害在某些方面存在潜伏期,危害一旦显现,治理难度极大,必须引起相关部门的高度重视。  相似文献   
89.
介绍了设计双流道筒体的必要性,通过建立物理、数学模型详细论述了双流道筒体的设计原理及换热计算过程,并通过试验对比分析验证了模型的可靠性,同时对单、双流道筒体的换热能力进行对比分析,得出了可靠的结论.  相似文献   
90.
Developing solar thermal power technology in an effective manner is a great challenge in China.In this paper an experiment platform of a parabolic trough solar collector system(PTCS) was developed for thermal power generation,and the performance of the PTCS was experimentally investigated with synthetic oil as the circulate heat transfer fluid(HTF).The solar collector's efficiency with the variation of the solar flux and the flow rate of the HTF was identified.The collector efficiency of the PTCS can be in ...  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