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   57102篇
  免费   4321篇
  国内免费   1914篇
电工技术   2670篇
技术理论   4篇
综合类   2579篇
化学工业   9759篇
金属工艺   2993篇
机械仪表   3299篇
建筑科学   2952篇
矿业工程   1363篇
能源动力   2010篇
轻工业   3756篇
水利工程   761篇
石油天然气   1967篇
武器工业   261篇
无线电   8329篇
一般工业技术   8616篇
冶金工业   3965篇
原子能技术   566篇
自动化技术   7487篇
  2024年   212篇
  2023年   903篇
  2022年   1618篇
  2021年   2277篇
  2020年   1735篇
  2019年   1477篇
  2018年   1709篇
  2017年   1722篇
  2016年   1660篇
  2015年   1987篇
  2014年   2523篇
  2013年   3453篇
  2012年   3431篇
  2011年   3930篇
  2010年   3208篇
  2009年   3210篇
  2008年   3132篇
  2007年   2748篇
  2006年   2518篇
  2005年   2099篇
  2004年   1744篇
  2003年   1803篇
  2002年   1976篇
  2001年   1671篇
  2000年   1281篇
  1999年   1172篇
  1998年   1429篇
  1997年   1045篇
  1996年   905篇
  1995年   729篇
  1994年   595篇
  1993年   469篇
  1992年   358篇
  1991年   297篇
  1990年   298篇
  1989年   261篇
  1988年   213篇
  1987年   187篇
  1986年   161篇
  1985年   149篇
  1984年   127篇
  1983年   85篇
  1982年   78篇
  1981年   74篇
  1980年   90篇
  1979年   54篇
  1978年   66篇
  1977年   64篇
  1976年   86篇
  1975年   44篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
Naïve Bayes learners are widely used, efficient, and effective supervised learning methods for labeled datasets in noisy environments. It has been shown that naïve Bayes learners produce reasonable performance compared with other machine learning algorithms. However, the conditional independence assumption of naïve Bayes learning imposes restrictions on the handling of real-world data. To relax the independence assumption, we propose a smooth kernel to augment weights for the likelihood estimation. We then select an attribute weighting method that uses the mutual information metric to cooperate with the proposed framework. A series of experiments are conducted on 17 UCI benchmark datasets to compare the accuracy of the proposed learner against that of other methods that employ a relaxed conditional independence assumption. The results demonstrate the effectiveness and efficiency of our proposed learning algorithm. The overall results also indicate the superiority of attribute-weighting methods over those that attempt to determine the structure of the network.  相似文献   
996.
This paper studies the effect of multiple geometric parameters of a micronozzle on a MEMS solid propellant thruster (MSPT) and establishes a quantitative optimisation model. Influences of the structural parameters of the micronozzle on performance are accurately calculated. The significance and contribution ratio of each parameter are evaluated by F distribution. Correspondingly, a horizontal MSPT is fabricated and tested to prove the optimisation model. In the implementation, a complete microigniter is formed by a single layer of Au, achieving an ultra-low ignition voltage of 2.1 V with an extremely low ignition resistance of 4 Ω.  相似文献   
997.
链接预测的一个关键问题在于如何合理高效地结合链接属性、节点属性等相关信息以用于预测的目的,针对该问题提出了一种基于节点影响力和兴趣的链接预测算法IPI(Influence Plus Interest),即通过拓扑结构信息来量化用户的影响力,通过文本信息来模拟用户兴趣.结合两类信息对节点间的联系进行打分,得分高的节点对即代表具有较强的联系.在真实数据集上的实验表明,我们提出的方法具有一定的可行性.  相似文献   
998.
Service recovery is a concept that involves regaining customer satisfaction and loyalty. Although existing studies have addressed its importance, few service recovery methodologies have been developed. Thus, there is a need to develop a systematic framework that can first detect customer status and then provide appropriate recovery recommendations to ensure customer satisfaction. This study develops such a framework in relation to an individual health maintenance practice. While regular moderate exercise is known to promote good health and help prevent disease, the lack of exercise remains a crucial health issue. This study presents a logistic regression model that uses both physiological data (heart rate and blood pressure) and psychological data (ratings of perceived exertion) to detect the effectiveness of an individual's exercise and to provide sports‐related service recovery suggestions as needed. To implement and assess this service recovery model, the use of a motion gaming system is proposed.  相似文献   
999.
This article presents a simulation method for the design of a digitally controlled oscillator (DCO). Electromagnetic (EM) simulations are essential and inevitable for modern LC oscillator design. Although EM‐simulators provide high accuracy, the EM‐simulation time is very long when metal‐oxide‐metal (MoM) capacitors are present. The proposed frame‐based EM‐simulation can significantly reduce the EM‐simulation time even in the presence of MoM capacitors without influencing the accuracy. To verify the proposed method, a DCO was fabricated using a 55‐nm CMOS process. Measurements of the DCO are in good agreement with the frame‐based post‐layout simulation results. In addition, the DCO has good performances with a low power consumption of approximately 0.68 mW.  相似文献   
1000.
Mining web facial images on the internet has become as a profitable and important paradigm towards auto face annotation technique. The unsupervised label refinement (ULR) is an effective method that can fix weakly labeled facial images data which are collected from the internet and included some images with wrong label. In order to improve the correction accuracy of ULR, particle swarm optimization (PSO) and binary particle swarm optimization (BPSO) are used for solving binary constraint optimization task in this study. A novel method named safe binary particle swam optimization (SBPSO) is also proposed to improve BPSO which has the probability over range problem for using the ULR. In addition, SBPSO is also employed for an enhanced ULR (EULR) objective function which is created by modifying the original formula of ULR to improve the accuracy of labeled facial image. An experimental database is queried from IMDb website which collected the actors who were bored in 1950 to 1990. Some error flags are randomly added in the database for the correction tests by different methods. The results showed that the SBPSO Algorithm for the EULR in automatic face annotation have the better label correction rate and convergence effect.  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