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   1702篇
  免费   147篇
  国内免费   14篇
电工技术   37篇
综合类   12篇
化学工业   399篇
金属工艺   39篇
机械仪表   90篇
建筑科学   78篇
矿业工程   3篇
能源动力   121篇
轻工业   112篇
水利工程   29篇
石油天然气   67篇
无线电   126篇
一般工业技术   323篇
冶金工业   51篇
原子能技术   13篇
自动化技术   363篇
  2024年   8篇
  2023年   29篇
  2022年   44篇
  2021年   88篇
  2020年   99篇
  2019年   127篇
  2018年   174篇
  2017年   148篇
  2016年   148篇
  2015年   89篇
  2014年   135篇
  2013年   194篇
  2012年   127篇
  2011年   134篇
  2010年   90篇
  2009年   76篇
  2008年   47篇
  2007年   39篇
  2006年   16篇
  2005年   8篇
  2004年   14篇
  2003年   5篇
  2002年   6篇
  2001年   2篇
  2000年   1篇
  1998年   5篇
  1995年   1篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1981年   1篇
排序方式: 共有1863条查询结果,搜索用时 31 毫秒
71.
Metallurgical and Materials Transactions A - In this research, it was found that the C/SiC transition interface thickness increases without a significant decrease in toughness by modifying the...  相似文献   
72.
Reliability of the current microprocessor technology is seriously challenged by radiation-induced soft errors. Accurate Vulnerability Factor (VF) modeling of system components is crucial in designing cost-effective protection schemes in high-performance processors. Although Statistical Fault Injection (SFI) techniques can be used to provide relatively accurate VF estimations, they are often very time-consuming. Unlike SFI techniques, recently proposed analytical models can be used to compute VF in a timely fashion. However, VFs computed by such models are inaccurate as the system-level impact of soft errors is overlooked.  相似文献   
73.
In this paper, the impact of the mixture of sodium dodecyl sulfate (SDS) + multi-wall carbon nanotubes (MWCNTs) + β-cyclodextrin on the quantity and initial rate of methane dissolved in water is investigated. The experiments were performed at a temperature range of 278.15–303.15 K and an initial pressure of 0.5 MPa. The experimental results show that simultaneous utilization of β-cyclodextrin (0.01 mass fraction), MWCNTs (0.0005 mass fraction), and SDS (0.001 mass fraction) at 278.15 K increases the amount and the rate of methane dissolution in water by 29.90% and 173.78%, respectively, compared to pure water. An increase in the temperature decreases the quantity and the initial rate of methane dissolution in all solutions containing additives. However, no consistent relationship is observed between the temperature and the enhancement percentage of solubility of methane in solutions containing additives.  相似文献   
74.
This study employs a design science perspective to propose a methodology for open strategic planning (OSP). Habermas’ discourse theory and Bryson’s strategy change cycle are used as informing kernel theories. A methodology is proposed to satisfy the requirements retrieved from the kernel theories. The proposed methodology contains modules for a planning system and a planning process. Design principles are explained through a blueprint of the system and process. The proposed methodology is applied and evaluated in two cases. Contributions to the literature involve extending the literature on OSP to an applicable methodology with guidelines on how to implement open strategy.  相似文献   
75.
76.
The increasing global energy demand and declination of oil reservoir in recent years cause the researchers attention focus on the enhancement of oil recovery approaches. One of the extensive applicable methods for enhancement of oil recovery, which has great efficiency and environmental benefits, is carbon dioxide injection. The CO2 injection has various effects on the reservoir fluid, which causes enhancement of recovery. One of these effects is extraction of lighter components of crude oil, which straightly depends on solubility of hydrocarbons in carbon dioxide. In order to better understand of this parameter, in this study, Least squares support vector machine (LSSVM) algorithm was developed as a novel predictive tool to estimate solubility of alkane in CO2 as function of carbon number of alkane, carbon dioxide density, pressure, and temperature. The predicting model outputs were compared with the extracted experimental solubility from literature statistically and graphically. The comparison showed the great ability and high accuracy of developed model in prediction of solubility.  相似文献   
77.
Two auto-calibration methods, namely Nelder-Mead (NM) and Univariate-Gradient (UG) and a manual approach are available for calibrating the HEC-HMS program. However, their being either inefficient or time consuming makes it difficult to work with HEC-HMS especially when using a snowmelt module in a continuous mode. The main objective of this paper is to develop an efficient Genetic Algorithm (GA) based auto-calibration method for HEC-HMS model (HMS-GA) for continuous snowmelt simulation. A general novel procedure is presented in the absence of the HMS source code to link a heuristic algorithm with the HEC program through Jython programming language. The models are developed and evaluated using daily data from basins in Ajichai, northwestern Iran. A comparison of results for a verification period indicates a substantial improvement by applying the HMS-GA over the other available methods. Moreover, it is shown that neither NM nor UG is able to improve the results obtained by either the manual or HMS-GA. Furthermore, the proposed method significantly improves the calibrations of the HMS model found by the three other methods.  相似文献   
78.
Mechanics of Time-Dependent Materials - The aim of this study is to investigate the role of chain length and hard segment dispersion within the soft segment on thermo-mechanical properties of a...  相似文献   
79.
80.
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