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   3510篇
  免费   209篇
  国内免费   8篇
电工技术   41篇
化学工业   862篇
金属工艺   47篇
机械仪表   86篇
建筑科学   140篇
矿业工程   6篇
能源动力   114篇
轻工业   636篇
水利工程   31篇
石油天然气   21篇
无线电   239篇
一般工业技术   498篇
冶金工业   165篇
原子能技术   13篇
自动化技术   828篇
  2024年   10篇
  2023年   45篇
  2022年   130篇
  2021年   151篇
  2020年   120篇
  2019年   135篇
  2018年   132篇
  2017年   119篇
  2016年   155篇
  2015年   120篇
  2014年   158篇
  2013年   300篇
  2012年   253篇
  2011年   290篇
  2010年   220篇
  2009年   205篇
  2008年   191篇
  2007年   166篇
  2006年   134篇
  2005年   105篇
  2004年   84篇
  2003年   72篇
  2002年   74篇
  2001年   37篇
  2000年   35篇
  1999年   31篇
  1998年   49篇
  1997年   30篇
  1996年   29篇
  1995年   24篇
  1994年   13篇
  1993年   20篇
  1992年   9篇
  1991年   9篇
  1990年   8篇
  1989年   6篇
  1988年   3篇
  1987年   2篇
  1986年   2篇
  1985年   6篇
  1984年   4篇
  1983年   5篇
  1982年   3篇
  1981年   7篇
  1978年   3篇
  1977年   6篇
  1976年   5篇
  1974年   2篇
  1973年   5篇
  1945年   1篇
排序方式: 共有3727条查询结果,搜索用时 8 毫秒
111.
The Chilean Ministry of Education oversees preschool, primary, and secondary education in both urban and rural areas. Many parts of Chile are sparsely populated and there are currently over 4,000 rural schools (almost 38% of all schools in Chile) educating 9.5% of the students in the country. Many of the rural schools are small with only one teacher responsible for instruction of all local students (multigrade schools). The geographical distribution of the rural schools has not been coordinated and this has resulted in unequal utilization of existing schools and some unreasonably long travel distances by students. Good management of the rural schools is fundamental to meeting Chile's goal of providing quality education to its citizens. Seeking to improve the situation, the Ministry of Education ordered a study of the optimal location and size of rural schools with the general goals of reducing the number of lesser quality multigrade schools and reducing student travel distances while maintaining reasonable costs. This paper presents results of this study obtained using an integer linear program that has been embedded in a geographical information system. We present computational results for the entire country. Recommendations include where to open new rural schools as well as where to expand, reduce, close, or leave unchanged existing schools. We show how recommendations are sensitive to key parameters such as the cost of transportation.  相似文献   
112.
The traditional approach for specifying adaptive behavior in embedded applications requires developers to engage in error-prone programming tasks. This results in long design cycles and in the inherent inability to explore and evaluate a wide variety of alternative adaptation behaviors, critical for systems exposed to dynamic operational and situational environments. In this paper, we introduce a domain-specific language (DSL) for specifying and implementing run-time adaptable application behavior. We illustrate our approach using a real-life stereo navigation application as a case study, highlighting the impact and benefits of dynamically adapting algorithm parameters. The experiments reveal our approach effective, as such run-time adaptations are easily specified in a higher level by the DSL, and thus at a lower programming effort than when using a general-purpose language such as C.  相似文献   
113.
Working with forestry machines requires a great deal of training to be sufficiently skilled to operate forestry cranes. In view of this, it would be desirable within the forestry industry to introduce automated motions, such as those seen in robotic arms, to shorten the training time and make the work of the operator easier. Motivated by this fact, we have developed two experimental platforms for testing control systems and motion‐planning algorithms in real time. They correspond to a laboratory setup and a commercial version of a hydraulic manipulator used in forwarder machines. The aim of this article is to present the results of this development by providing an overview of our trajectory‐planning algorithm and motion‐control method, with a subsequent view of the experimental results. For motion control, we design feedback controllers that are able to track reference trajectories based on sensor measurements. Likewise, we provide arguments to design controllers in an open‐loop for machines that lack sensing devices. Relying on the tracking efficiency of these controllers, we design time‐efficient reference trajectories of motions that correspond to logging tasks. To demonstrate performance, we provide an overview of extensive testing done on these machines.  相似文献   
114.
International Journal on Software Tools for Technology Transfer - Current real-time embedded systems development frameworks lack support for the verification of properties using explicit time where...  相似文献   
115.
Utilization of expert recommendations in the development of food and beverage nutritional profiles represents an opportunity to merge science and food manufacturing to deliver nutritionally optimized products into the marketplace. This report details expert panel guidelines for the design of a nutritional product for children one to six years of age. This interaction demonstrates the essential synergy between academia and food manufacturers in translating nutrient recommendations to food for their delivery to a population. Important factors for such translation are the identification of applicable nutrient recommendations and selection of an appropriate delivery matrix. This report demonstrates the translation of expert nutritional recommendations to a milk-based product for children—one to six years of age.  相似文献   
116.
This work was aimed at determining the feasibility of artificial neural networks (ANN) by implementing backpropagation algorithms with default settings to generate better predictive models than multiple linear regression (MLR) analysis. The study was hypothesized on timolol-loaded liposomes. As tutorial data for ANN, causal factors were used, which were fed into the computer program. The number of training cycles has been identified in order to optimize the performance of the ANN. The optimization was performed by minimizing the error between the predicted and real response values in the training step. The results showed that training was stopped at 10?000 training cycles with 80% of the pattern values, because at this point the ANN generalizes better. Minimum validation error was achieved at 12 hidden neurons in a single layer. MLR has great prediction ability, with errors between predicted and real values lower than 1% in some of the parameters evaluated. Thus, the performance of this model was compared to that of the MLR using a factorial design. Optimal formulations were identified by minimizing the distance among measured and theoretical parameters, by estimating the prediction errors. Results indicate that the ANN shows much better predictive ability than the MLR model. These findings demonstrate the increased efficiency of the combination of ANN and design of experiments, compared to the conventional MLR modeling techniques.  相似文献   
117.
118.
In this paper we present the use of static temperature measurements as process variation observable. Contrary to previously published thermal testing methods, the proposed methodology does not need an excitation signal, thus reducing test cost and improving built-in capabilities of thermal monitoring. The feasibility of the technique and a complete test methodology is presented using a narrowband LNA as example. Finally, a complete electro-thermal co-simulation test bench between the LNA and a differential temperature sensor embedded in the same silicon die is presented in order to validate the results. Results prove that RF figures of merit can be extracted from DC temperature measurements done without loading or exciting the RF circuit under test.  相似文献   
119.
120.
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