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   13545篇
  免费   970篇
  国内免费   110篇
电工技术   205篇
综合类   61篇
化学工业   3538篇
金属工艺   346篇
机械仪表   489篇
建筑科学   516篇
矿业工程   21篇
能源动力   951篇
轻工业   1277篇
水利工程   188篇
石油天然气   224篇
武器工业   4篇
无线电   1378篇
一般工业技术   2530篇
冶金工业   490篇
原子能技术   95篇
自动化技术   2312篇
  2024年   70篇
  2023年   268篇
  2022年   587篇
  2021年   891篇
  2020年   751篇
  2019年   812篇
  2018年   911篇
  2017年   828篇
  2016年   807篇
  2015年   474篇
  2014年   749篇
  2013年   1366篇
  2012年   903篇
  2011年   950篇
  2010年   665篇
  2009年   596篇
  2008年   419篇
  2007年   355篇
  2006年   302篇
  2005年   192篇
  2004年   174篇
  2003年   152篇
  2002年   119篇
  2001年   91篇
  2000年   90篇
  1999年   81篇
  1998年   137篇
  1997年   114篇
  1996年   96篇
  1995年   68篇
  1994年   51篇
  1993年   59篇
  1992年   46篇
  1991年   38篇
  1990年   40篇
  1989年   32篇
  1988年   25篇
  1987年   24篇
  1986年   34篇
  1985年   27篇
  1984年   27篇
  1983年   25篇
  1982年   21篇
  1981年   19篇
  1980年   19篇
  1979年   16篇
  1978年   18篇
  1977年   18篇
  1976年   24篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.

Shear connectors play a prominent role in the design of steel-concrete composite systems. The behavior of shear connectors is generally determined through conducting push-out tests. However, these tests are costly and require plenty of time. As an alternative approach, soft computing (SC) can be used to eliminate the need for conducting push-out tests. This study aims to investigate the application of artificial intelligence (AI) techniques, as sub-branches of SC methods, in the behavior prediction of an innovative type of C-shaped shear connectors, called Tilted Angle Connectors. For this purpose, several push-out tests are conducted on these connectors and the required data for the AI models are collected. Then, an adaptive neuro-fuzzy inference system (ANFIS) is developed to identify the most influencing parameters on the shear strength of the tilted angle connectors. Totally, six different models are created based on the ANFIS results. Finally, AI techniques such as an artificial neural network (ANN), an extreme learning machine (ELM), and another ANFIS are employed to predict the shear strength of the connectors in each of the six models. The results of the paper show that slip is the most influential factor in the shear strength of tilted connectors and after that, the inclination angle is the most effective one. Moreover, it is deducted that considering only four parameters in the predictive models is enough to have a very accurate prediction. It is also demonstrated that ELM needs less time and it can reach slightly better performance indices than those of ANN and ANFIS.

  相似文献   
112.

An analytical answer to the buckling problem of a composite plate consisted of multi-scale hybrid nanocomposites is presented here for the first time. In other words, the constituent material of the structure is made of an epoxy matrix which is reinforced by both macro- and nanosize reinforcements, namely, carbon fiber (CF) and carbon nanotube (CNT). The effective material properties such as Young’s modulus or density are derived utilizing a micromechanical scheme incorporated with the Halpin–Tsai model. To present a more realistic problem, the plate is placed on a two-parameter elastic substrate. Then, on the basis of an energy-based Hamiltonian approach, the equations of motion are derived using the classical theory of plates. Finally, the governing equations are solved analytically to obtain the critical buckling load of the system. Afterward, the normalized form of the results is presented to emphasize the impact of each parameter on the dimensionless buckling load of composite plates. It is worth mentioning that the effects of various boundary conditions are covered, too. To show the efficiency of presented modeling, the results of this article are compared to those of former attempts.

  相似文献   
113.
The Journal of Supercomputing - Agile software development (ASD) and software product line (SPL) have shown significant benefits for software engineering processes and practices. Although both...  相似文献   
114.
Neural Computing and Applications - In order to provide benchmark performance for Urdu text document classification, the contribution of this paper is manifold. First, it provides a publicly...  相似文献   
115.
Microsystem Technologies - In this research we present an algorithm for a six-wheeled robotic vehicle with articulated suspension (RVAS) to estimate the vehicle velocity and acceleration states,...  相似文献   
116.
Microsystem Technologies - In this research a biologically inspired finger-like mechanism similar to human musculoskeletal system is developed based on Shape Memory Alloys (SMAs). SMA actuators are...  相似文献   
117.
Neural Computing and Applications - In this work, we conducted an empirical comparative study of the performance of text-independent speaker verification in emotional and stressful environments....  相似文献   
118.
Neural Computing and Applications - Lung cancer is a deadly disease if not diagnosed in its early stages. However, early detection of lung cancer is a challenging task due to the shape and size of...  相似文献   
119.
120.
A classifier combining strategy, virtual voting by random projection (VVRP), is presented. VVRP takes advantage from the bounded distortion incurred by random projection in order to improve accuracies of stable classifiers like discriminant analysis (DA) where existing classifier combining strategies are known to be failed. It uses the distortion to virtually generate different training sets from the total available training samples in a way that does not have the potential for overfitting. Then, a majority voting combines the base learners trained on these versions of the original problem. VVRP is very simple and just needs determining a proper dimensionality for the versions, an often very easy task. It is shown to be stable in a very large region of the hyperplane constructed by the dimensionality and the number of the versions. VVRP improves the best state-of-the-art DA algorithms in both small and large sample size problems in various classification fields.  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