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   1168篇
  免费   68篇
  国内免费   7篇
电工技术   20篇
综合类   3篇
化学工业   232篇
金属工艺   14篇
机械仪表   35篇
建筑科学   78篇
矿业工程   2篇
能源动力   48篇
轻工业   180篇
水利工程   12篇
石油天然气   11篇
武器工业   3篇
无线电   124篇
一般工业技术   192篇
冶金工业   82篇
原子能技术   8篇
自动化技术   199篇
  2024年   2篇
  2023年   12篇
  2022年   40篇
  2021年   56篇
  2020年   48篇
  2019年   51篇
  2018年   56篇
  2017年   50篇
  2016年   57篇
  2015年   36篇
  2014年   55篇
  2013年   93篇
  2012年   74篇
  2011年   75篇
  2010年   68篇
  2009年   58篇
  2008年   46篇
  2007年   56篇
  2006年   32篇
  2005年   26篇
  2004年   28篇
  2003年   21篇
  2002年   12篇
  2001年   10篇
  2000年   18篇
  1999年   25篇
  1998年   18篇
  1997年   24篇
  1996年   16篇
  1995年   7篇
  1994年   3篇
  1993年   4篇
  1992年   7篇
  1991年   3篇
  1990年   3篇
  1989年   7篇
  1988年   10篇
  1986年   4篇
  1985年   3篇
  1984年   5篇
  1983年   3篇
  1982年   1篇
  1981年   6篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1976年   2篇
  1975年   1篇
  1971年   1篇
  1970年   1篇
排序方式: 共有1243条查询结果,搜索用时 31 毫秒
21.
Gasmi  Karim 《The Journal of supercomputing》2022,78(13):15042-15059

Due to the increase in electronic documents containing medical information, the search for specific information is often complex and time-consuming. This has prompted the development of new tools designed to address this issue. Automated visual question/answer (VQA) systems are becoming more challenging to develop. These are computer programs that take images and questions as input and then combine all inputs to generate text-based answers. Due to the enormous amount of question and the limited number of specialists, many issues stay unanswered. It’s possible to solve this problem by using automatic question classifiers that guide queries to experts based on their subject preferences. For these purposes, we propose a VQA approach based on a hybrid deep learning model. The model consists of three steps: (1) the classification of medical questions based on a BERT model; (2) image and text feature extraction using a deep learning model, more specifically the extraction of medical image features by a hybrid deep learning model; and (3) text feature extraction using a Bi-LSTM model. Finally, to predict the appropriate answer, our approach uses a KNN model. Additionally, this study examines the influence of the Adam, AdaGrad, Stochastic gradient descent and RMS Prop optimization techniques on the performance of the network. As a consequence of the studies, it was shown that Adam and SGD optimization algorithms consistently produced higher outcomes. Experiments using the ImageCLEF 2019 dataset revealed that the suggested method increases BLEU and WBSS values considerably.

  相似文献   
22.
Let A be the generator of a strongly continuous semigroup T on the Hilbert space X, and let C be a linear operator from D(A) to another Hilbert space Y (possibly unbounded with respect to X, not necessarily admissible). We consider the problem of estimating the initial state z0D(A) (with respect to the norm of X) from the output function y(t)=CTtz0, given for all t in a bounded interval [0,τ]. We introduce the concepts of estimatability and backward estimatability for (A,C) (in a more general way than currently available in the literature), we introduce forward and backward observers, and we provide an iterative algorithm for estimating z0 from y. This algorithm generalizes various algorithms proposed recently for specific classes of systems and it is an attractive alternative to methods based on inverting the Gramian. Our results lead also to a very general formulation of Russell’s principle, i.e., estimatability and backward estimatability imply exact observability. This general formulation of the principle does not require T to be invertible. We illustrate our estimation algorithms on systems described by wave and Schrödinger equations, and we provide results from numerical simulations.  相似文献   
23.
The issue of fault detection and diagnosis (FDD) has gained widespread industrial interest in process condition monitoring applications. An innovative data-driven FDD methodology has been presented in this paper on the basis of a distributed configuration of three adaptive neuro-fuzzy inference system (ANFIS) classifiers for an industrial 440 MW power plant steam turbine with once-through Benson type boiler. Each ANFIS classifier has been developed for a dedicated category of four steam turbine faults. A preliminary set of conceptual and experimental studies has been conducted to realize such fault categorization scheme. A proper selection of four measured variables has been configured to feed each ANFIS classifier with the most influential diagnostic information. This consequently leads to a simple distributed FDD system, facilitating the training and testing phases and yet prevents operational deficiency due to possible cross-correlated measured data effects. A diverse set of test scenarios has been carried out to illustrate the successful diagnostic performances of the proposed FDD system against 12 major faults under challenging noise corrupted measurements and data deformation corresponding to a specific fault time history pattern.  相似文献   
24.
Consider a rooted tree T of arbitrary maximum degree d representing a collection of n web pages connected via a set of links, all reachable from a source home page represented by the root of T. Each web page i carries a probability p i representative of the frequency with which it is visited. By adding hotlinks—shortcuts from a node to one of its descendents—we wish to minimize the expected number of steps l needed to visit pages from the home page, expressed as a function of the entropy H(p) of the access probabilities p. This paper introduces several new strategies for effectively assigning hotlinks in a tree. For assigning exactly one hotlink per node, our method guarantees an upper bound on l of 1.141H(p)+1 if d>2 and 1.08H(p)+2/3 if d=2. We also present the first efficient general methods for assigning at most k hotlinks per node in trees of arbitrary maximum degree, achieving bounds on l of at most \frac2H(p)log(k+1)+1\frac{2H(p)}{\log(k+1)}+1 and \fracH(p)log(k+d)-logd+1\frac{H(p)}{\log(k+d)-\log d}+1 , respectively. All our methods are strong, i.e., they provide the same guarantees on all subtrees after the assignment. We also present an algorithm implementing these methods in O(nlog n) time, an improvement over the previous O(n 2) time algorithms. Finally we prove a Ω(nlog n) lower bound on the running time of any strong method that guarantee an average access time strictly better than 2H(p).  相似文献   
25.
In this paper, we present a thorough mathematical analysis of the use of neural networks to solve a specific classification problem consisting of a bilinear boundary. The network under consideration is a three-layered perceptron with two hidden neurons having the sigmoid serving as the activation function. The analysis of the hidden space created by the outputs of the hidden neurons will provide results on the network’s capacity to isolate two classes of data in a bilinear fashion, and the importance of the value of the sigmoid parameter is highlighted. We will obtain an explicit analytical function describing the boundary generated by the network, thus providing information on the effect each parameter has on the network’s behavior. Generalizations of the results are obtained with additional neurons, and a theorem concerned with analytical reproducibility of the boundary function is established.  相似文献   
26.
During the continuous casting of steel, several disturbances occur and affect all the parts of the caster, including the mould where the molten steel has to be stable for good quality of the final product. Especially at high casting velocities, the bulging generates important level fluctuations which cannot be efficiently rejected by the classical controllers. To address these problems, this paper proposes an architecture combining disturbances estimation and compensation techniques. It operates as an additional module and does not need any change of the main controller currently implemented. The entire structure has been tested successfully through several simulations and by means of intensive water model experiments.  相似文献   
27.
In this study, we propose to evaluate the potential of Raman spectroscopy (RS) to assess renal tumours at surgery. Different classes of Raman renal spectra acquired during a clinical protocol are discriminated using support vector machines classifiers. The influence on the classification scores of various preprocessing steps generally involved in RS are also investigated and evaluated in the particular context of renal tumour characterization. Encouraging results show the interest of RS to evaluate kidney cancer and suggest the potential of this technique as a surgical assistance during partial nephrectomy.  相似文献   
28.
The widespread use of the Internet and the convenient mechanism it provides, such as easy access, easy downloads, and easy copy and paste functions have made many types of unethical behaviors easier, particularly those involving students in academic settings. Among the issues in ethics within the academic environment that can be triggered by the Internet are fraudulence, plagiarism, falsification, delinquency, unauthorized help, and facility misuse. Given these issues, the study seeks to investigate the extent to which students at a public university in Malaysia engage in such unethical behavior and their relationship with the big five personality model. This study was conducted using a survey method of 252 students in three different academic faculties. The results of factor analyses confirm and refine the reliability of the scales for both big five personality variables and unethical Internet behaviors as conceptualized through Internet triggered academic dishonesty (ITADS). The findings indicate that personality traits such as (1) agreeableness, (2) conscientiousness and (3) emotional stability are significantly and negatively correlated with unethical Internet behavior in university students. Significant differences in facility misuse are also observed between the three academic faculties investigated. This research should provide significant contributions to educators in designing the computer ethics curriculum and in allowing for educational institutions as well as other organizations in developing relevant policies and guidelines on matters pertaining to academic conduct, utilization of computers and Internet, and recruitment exercises.  相似文献   
29.
30.
We describe the research and the integration methods we developed to make the HRP-2 humanoid robot climb vertical industrial-norm ladders. We use our multi-contact planner and multi-objective closed-loop control formulated as a QP (quadratic program). First, a set of contacts to climb the ladder is planned off-line (automatically or by the user). These contacts are provided as an input for a finite state machine. The latter builds supplementary tasks that account for geometric uncertainties and specific grasps procedures to be added to the QP controller. The latter provides instant desired states in terms of joint accelerations and contact forces to be tracked by the embedded low-level motor controllers. Our trials revealed that hardware changes are necessary, and parts of software must be made more robust. Yet, we confirmed that HRP-2 has the kinematic and power capabilities to climb real industrial ladders, such as those found in nuclear power plants and large scale manufacturing factories (e.g. aircraft, shipyard) and construction sites.  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