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   1283篇
  免费   148篇
  国内免费   1篇
电工技术   21篇
化学工业   404篇
金属工艺   61篇
机械仪表   36篇
建筑科学   30篇
矿业工程   5篇
能源动力   47篇
轻工业   225篇
水利工程   11篇
石油天然气   5篇
无线电   54篇
一般工业技术   319篇
冶金工业   24篇
原子能技术   16篇
自动化技术   174篇
  2023年   15篇
  2022年   12篇
  2021年   51篇
  2020年   40篇
  2019年   54篇
  2018年   68篇
  2017年   68篇
  2016年   59篇
  2015年   78篇
  2014年   102篇
  2013年   218篇
  2012年   67篇
  2011年   63篇
  2010年   77篇
  2009年   58篇
  2008年   28篇
  2007年   19篇
  2006年   21篇
  2005年   9篇
  2004年   13篇
  2003年   8篇
  2002年   8篇
  2001年   15篇
  2000年   20篇
  1999年   8篇
  1998年   8篇
  1997年   11篇
  1996年   13篇
  1995年   11篇
  1994年   9篇
  1993年   12篇
  1992年   9篇
  1991年   11篇
  1990年   6篇
  1989年   6篇
  1988年   8篇
  1987年   7篇
  1986年   9篇
  1985年   12篇
  1984年   12篇
  1983年   15篇
  1982年   8篇
  1981年   18篇
  1980年   7篇
  1979年   6篇
  1977年   6篇
  1976年   8篇
  1975年   7篇
  1974年   9篇
  1973年   5篇
排序方式: 共有1432条查询结果,搜索用时 15 毫秒
91.
Catches ofDendroctonus frontalis andIps avulsus on traps surrounding bolts infested with both sexes of each species in the gallery were not significantly different from catches at bolts infested only with the sex which normally pioneers the host colonization process. In contrast, the presence of the second sex in the gallery significantly reduced catches ofI. grandicollis andI. calligraphus and, additionally, the presence of females in the male galleries ofI. calligraphus significantly reduced the catch ofI. avulsus females as compared with their response to bolts infested with the maleI. calligraphus only.  相似文献   
92.
93.
Summary In acid medium and at temperatures from 50 to 100°C the resins from three different guanamines and three different unsaturated aldehydes were synthesized. The products were red coloured resins, which were soluble in organic solvents and were able to cure with hexamethylenetetramine to form hard and almost insoluble products. Using a combination of NMR and GPC methods it was possible to predict the course and the mechanism of the reactions. The rates of the reactions depend on the reaction conditions and on the type of the monomer.  相似文献   
94.
The paper presents a general methodology of adaptive control based on fuzzy model to deal with unknown plants. The problem of parameter estimation is solved using a direct approach, i.e. the controller parameters are adapted without explicitly estimating plant parameters. Thus, very simple adaptive and control laws are obtained using Lyapunov stability criterion. The generality of the approach is substantiated by Stone-Weierstrass theorem, which indicates that any continuous function can be approximated by fuzzy basis function expansion. In the sense of adaptive control, this implies the adaptive law with fuzzified adaptive control parameters. The proposed control algorithm may be viewed as an extension of classical adaptive control for linear plants, but compared to the latter it provides higher adaptation ability and consequently better performance if the plant is nonlinear. The global stability of the control system is assured and the tracking error converges to the residual set that depends on fuzzification properties. The main advantage of the approach is simplicity that suits control engineers since wide range of industrial processes can be controlled by the proposed method. In the paper, the control of heat exchanger is performed.  相似文献   
95.
Theoretical and Empirical Analysis of ReliefF and RReliefF   总被引:23,自引:0,他引:23  
Relief algorithms are general and successful attribute estimators. They are able to detect conditional dependencies between attributes and provide a unified view on the attribute estimation in regression and classification. In addition, their quality estimates have a natural interpretation. While they have commonly been viewed as feature subset selection methods that are applied in prepossessing step before a model is learned, they have actually been used successfully in a variety of settings, e.g., to select splits or to guide constructive induction in the building phase of decision or regression tree learning, as the attribute weighting method and also in the inductive logic programming.A broad spectrum of successful uses calls for especially careful investigation of various features Relief algorithms have. In this paper we theoretically and empirically investigate and discuss how and why they work, their theoretical and practical properties, their parameters, what kind of dependencies they detect, how do they scale up to large number of examples and features, how to sample data for them, how robust are they regarding the noise, how irrelevant and redundant attributes influence their output and how different metrics influences them.  相似文献   
96.
97.
98.
Low-latency transmissions of high resolution video such as HD, 2K, or 4K over both Internet and private IP networks have found a foothold in many interactive applications, ranging from collaborative environments in science and medicine to the arts and entertainment industry. In this paper we demonstrate how the power of commodity graphics processing units can be used for efficient implementation of JPEG and DXT compression. We propose an approach to fine-grained parallelization of JPEG compression and the use of auxiliary indexes for efficient decompression, which are backward compatible with the JPEG standard. In-depth performance analysis is provided to show various aspects of the proposed parallelization including the dependency on image content and on various settings of the compression algorithm, as well as the impact of compression for interactive applications in terms of end-to-end latency. The applicability of these compression schemes in medicine and cinematography has also been evaluated using double-blind ABX tests compared with uncompressed video. We describe selected successful real-world deployment use cases based on our open-source implementation within the UltraGrid framework, such as trans-Atlantic 4K interactive video streaming during the CineGrid 2011 workshop. As discussed in the paper, the proposed approaches to parallelization provide sufficient performance even for the future generation of 8K video processing systems, currently limited by availability of camera and display hardware.  相似文献   
99.
The article introduces, as a result of further development of the first-order scheme NICE, a simple and efficient higher-order explicit numerical scheme for the integration of a system of ordinary differential equations which is constrained by an algebraic condition (DAE). The scheme is based on the truncated Taylor expansion of the constraint equation with order h of the scheme being determined by the highest exponent in the truncated Taylor series. The integration scheme thus conceived will be named NICE h , considering both principal premises of its construction. In conjunction with a direct solution technique used to solve the boundary value problem, the NICE h scheme is very convenient for integrating constitutive models in plasticity. The plasticity models are defined mostly by a system of algebraic and differential equations in which the yield criterion represents the constraint condition. To study the properties of the new integration scheme, which, like the forward-Euler scheme, is characterised by its implementation simplicity due to the explicitness of its formulations, a damage constitutive model (Gurson–Tvergaard–Needleman model) is considered. The general opinion that the implicit backward-Euler scheme is much more accurate than the thus-far known explicit schemes is challenged by the introduction of the NICE h scheme. The accuracy of the higher-order explicit scheme in the studied cases is significantly higher than the accuracy of the classical backward-Euler scheme, if we compare them under the condition of a similar CPU time consumption.  相似文献   
100.
Organizations should look at humans as multilayered, not only as professional entities. In synergy, not only individually, we define humans as: (1) physical, (2) mental, (3) social, (4) spiritual, and (5) economic entities, marked by requisitely holistic patterns of relatively permanent characteristics, due to which individuals differ from each other; they differ also as specialized professionals. All these and other attributes form synergies. On this basis, the behavior of individuals who are willing to practice interdisciplinary cooperation becomes socially responsible and they have a high level of well-being.

Individuals as well as organizations seek requisite personal holism (RPH) on the one hand and psychic well-being (PWB) on the other hand. Thus, individuals implement individual techniques and organizations implement special strategies, programs, and actions in the frame of human resource management (HRM). That is how organizations in the frame of HRM, more specifically in the frame of management well-being, are developing special programs for managing PWB. These programs are based on their RPH and organizations might help employees to feel respected and valued in their work settings, without regard to their culture, religion, ethnicity, gender, age, disability, or other individual differences. The most-often applied programs of the kind include: (1) stress management programs, (2) diversity management programs, (3) wellness programs, (4) employee assistance programs, and (5) programs for personal growth.  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