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   784070篇
  免费   9204篇
  国内免费   2233篇
电工技术   14192篇
综合类   1015篇
化学工业   119846篇
金属工艺   34088篇
机械仪表   25646篇
建筑科学   17905篇
矿业工程   5347篇
能源动力   19742篇
轻工业   61172篇
水利工程   9361篇
石油天然气   18314篇
武器工业   76篇
无线电   85212篇
一般工业技术   160846篇
冶金工业   134330篇
原子能技术   18792篇
自动化技术   69623篇
  2021年   6779篇
  2019年   6444篇
  2018年   15144篇
  2017年   15398篇
  2016年   14333篇
  2015年   7778篇
  2014年   12863篇
  2013年   34163篇
  2012年   21218篇
  2011年   31180篇
  2010年   25560篇
  2009年   27544篇
  2008年   28171篇
  2007年   28994篇
  2006年   21198篇
  2005年   21035篇
  2004年   19820篇
  2003年   19279篇
  2002年   18105篇
  2001年   17334篇
  2000年   16572篇
  1999年   16647篇
  1998年   39156篇
  1997年   28306篇
  1996年   21929篇
  1995年   16897篇
  1994年   15140篇
  1993年   14951篇
  1992年   11353篇
  1991年   11023篇
  1990年   10738篇
  1989年   10489篇
  1988年   9988篇
  1987年   9040篇
  1986年   8863篇
  1985年   9935篇
  1984年   9062篇
  1983年   8582篇
  1982年   7799篇
  1981年   7915篇
  1980年   7645篇
  1979年   7576篇
  1978年   7526篇
  1977年   8299篇
  1976年   10543篇
  1975年   6661篇
  1974年   6401篇
  1973年   6476篇
  1972年   5519篇
  1971年   5071篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance.  相似文献   
93.
94.
Theoretical Foundations of Chemical Engineering - New research results, as well as those published earlier by the authors, on the synthesis of azo compounds based on nitroanilines obtained by the...  相似文献   
95.
In the future, hydrogen will be an important energy carrier and industrial raw material. Catalytic steam reforming of bio-oils is a promising and economically viable technology for hydrogen production. However, during the reforming process, the catalysts are rapidly deactivated due to coke formation and sintering. Thus, maintaining the activity and stability of catalysts is the key issue in this process. Optimized operation conditions could extend the catalyst lifetime by affecting the coke morphology or promoting coke gasification. This article summarizes the recent developments in the field of catalytic steam reforming of bio-oils, focusing on the operation conditions, the properties of the catalysts, and the effects of the catalyst supports. The expected insights into the catalytic steam reforming of bio-oils will provide further guidance for hydrogen production from bio-oils.  相似文献   
96.
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with...  相似文献   
97.
At the hydroelectric unit No. 11 of the Nizhnekamsk hydroelectric power plant, the filling wedges of a rotor were investigated by ultrasound in the free st  相似文献   
98.
Traditionally, in supervised machine learning, (a significant) part of the available data (usually 50%-80%) is used for training and the rest—for validation. In many problems, however, the data are highly imbalanced in regard to different classes or does not have good coverage of the feasible data space which, in turn, creates problems in validation and usage phase. In this paper, we propose a technique for synthesizing feasible and likely data to help balance the classes as well as to boost the performance in terms of confusion matrix as well as overall. The idea, in a nutshell, is to synthesize data samples in close vicinity to the actual data samples specifically for the less represented (minority) classes. This has also implications to the so-called fairness of machine learning. In this paper, we propose a specific method for synthesizing data in a way to balance the classes and boost the performance, especially of the minority classes. It is generic and can be applied to different base algorithms, for example, support vector machines, k-nearest neighbour classifiers deep neural, rule-based classifiers, decision trees, and so forth. The results demonstrated that (a) a significantly more balanced (and fair) classification results can be achieved and (b) that the overall performance as well as the performance per class measured by confusion matrix can be boosted. In addition, this approach can be very valuable for the cases when the number of actual available labelled data is small which itself is one of the problems of the contemporary machine learning.  相似文献   
99.
Russian Journal of Non-Ferrous Metals - Rolling bearing rings comprise a large reserve for expanding powder metallurgy production. This reserve is being incompletely implemented. The hot forging of...  相似文献   
100.
Journal of Communications Technology and Electronics - Abstract—The two-dimensional diffraction problem of a plane polarized TM-wave on two identical solid silver nanocylinders is considered....  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