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   386015篇
  免费   29333篇
  国内免费   18037篇
电工技术   21290篇
技术理论   61篇
综合类   45794篇
化学工业   54872篇
金属工艺   17532篇
机械仪表   17156篇
建筑科学   55427篇
矿业工程   20887篇
能源动力   14333篇
轻工业   24515篇
水利工程   30260篇
石油天然气   19605篇
武器工业   2818篇
无线电   18776篇
一般工业技术   25740篇
冶金工业   23520篇
原子能技术   4337篇
自动化技术   36462篇
  2024年   1288篇
  2023年   3954篇
  2022年   7846篇
  2021年   9445篇
  2020年   9893篇
  2019年   8081篇
  2018年   7743篇
  2017年   9439篇
  2016年   10909篇
  2015年   11743篇
  2014年   21974篇
  2013年   20746篇
  2012年   26357篇
  2011年   27575篇
  2010年   21775篇
  2009年   22695篇
  2008年   20297篇
  2007年   26887篇
  2006年   25456篇
  2005年   22310篇
  2004年   18853篇
  2003年   17022篇
  2002年   14194篇
  2001年   11851篇
  2000年   9930篇
  1999年   7985篇
  1998年   5996篇
  1997年   5147篇
  1996年   4537篇
  1995年   3947篇
  1994年   3338篇
  1993年   2518篇
  1992年   2236篇
  1991年   1661篇
  1990年   1394篇
  1989年   1302篇
  1988年   988篇
  1987年   730篇
  1986年   548篇
  1985年   476篇
  1984年   442篇
  1983年   316篇
  1982年   255篇
  1981年   181篇
  1980年   150篇
  1979年   131篇
  1978年   68篇
  1977年   83篇
  1976年   60篇
  1975年   58篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Buffalo milk Cheddar cheese samples of different ages were analysed for compositional attributes (CA), ripening indices (RI) and Instron Textural Profile (ITP). All samples were compositionally alike, except for pH and salt-in-moisture (SM) contents. RI showed significant variations. CA and RI showed highly significant correlations within themselves and with each other, except for moisture with pH, SM with moisture, MNFS, Fat and FDM and Fat with MNFS. The ITPs of cheeses showed significant variations and had highly significant intercorrelations indicating their interdependence. CA (except moisture and MNFS) and RI showed a highly significant correlationship with ITPs. Moisture content showed a highly significant correlationship with all ITPs, except cohesiveness and springiness, where it was significant. MNFS content showed significant correlations only with hardness and brittleness. Stepwise regression analysis revealed that MI was the most predominant factor influencing cheese texture, followed by pH, SM, FDM and TVFA. Knowing Ca and RI, the textural properties of cheeses can be forecast through mathematical equations. Similarly the age of cheese can also be predicted if RI and/or textural properties are known.  相似文献   
102.
钛容器的特点   总被引:2,自引:1,他引:1  
根据钛材的化学、物理、力学和工艺性能介绍了钛容器在设计、制造、检验和应用方面的特点。  相似文献   
103.
In executing tasks involving intelligent information processing, the human brain performs better than the digital computer. The human brain derives its power from a large number [O(1011)] of neurons which are interconnected by a dense interconnection network [O(105) connections per neuron]. Artificial neural network (ANN) paradigms adopt the structure of the brain to try to emulate the intelligent information processing methods of the brain. ANN techniques are being employed to solve problems in areas such as pattern recognition, and robotic processing. Simulation of ANNs involves implementation of large number of neurons and a massive interconnection network. In this paper, we discuss various simulation models of ANNs and their implementation on distributed memory systems. Our investigations reveal that communication-efficient networks of distributed memory systems perform better than other topologies in implementing ANNs.  相似文献   
104.
What has become known as Community Operational Research has been around in the UK for many years. The election of Jonathan Rosenhead as President of the UK OR Society in 1986–87 was the catalyst for bringing together and expanding activities which had been carried out largely by individuals working in isolation on a voluntary basis. The following five years have seen the establishment of the Community OR Unit at Northern College, the Centre for Community OR at Hull University and the Community OR Network, which supports the activities of volunteer OR workers across the UK. This paper reviews the range and types of work which have been undertaken by various practitioners. An assessment of the success of community OR is made and a number of issues which have arisen are discussed. Finally, given the diverse nature of community OR, its practice and practitioners, there is some discussion about the future of the area.  相似文献   
105.
The hydrolysis of isocyanic acid in the gaseous phase has been investigated at temperatures between 553 and 613 K by mass spectrometry and evaluated to obtain the corresponding kinetic data. The reaction order and reaction constant have been determined. Finally, the influence of water on the catalysed formation of melamine from isocyanic acid under the operating conditions employed has been investigated in order to determine whether there is a need to try the process gas.  相似文献   
106.
对洪水分级的浅见   总被引:1,自引:0,他引:1  
洪水的等级划分应考虑流量、水位、防洪能力及灾害等因素,综合这些因素把洪水分成5个等级。1、2级洪水,洪水流量小,水位低,基本无灾;3级洪水,洪水流量较大或水位较高,有一定灾害;4级洪水,为大洪水或高水位,有较大灾害;5级洪水,为特大洪水或高水位,灾情严重。  相似文献   
107.
This paper highlights the possibility of inverse gas chromatography for the surface characterization of common fillers (CaCO3, talc, SiO2,) for paints and coatings. Divided solids are described, on the one hand, by the dispersive component of their surface energy and, on the other, by a specific parameter indicating their acid-base interaction potential. The role of the surface morphology at a molecular level is also examined. It is demonstrated that steric effects play an important role in the adsorption of probes on lamellar solids like talc. The consequences of surface treatments as well as examples of practical applications are also reported.  相似文献   
108.
Editorial.     
With this volume, the 47-year old Canadian Journal of Psychology takes a new name and makes a renewed commitment. In retitling the journal the Canadian Journal of Experimental Psychology, the intention is to reflect more clearly what has always been the major goal of the journal--to publish the best new research in experimental psychology, both Canadian and international, in both French and English. I am honoured to become the tenth editor of the major journal for experimental psychology in Canada. CJP has served the field very well; my primary goal is to ensure that CJEP continues to do so. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
109.
Treatment of the addictions is changing. Psychosocial treatment programs and research projects have changed the way helping professionals view, treat, and prevent drug abuse. This article reviews the contributions included in this special series; they encompass several general issues facing psychologists who conduct treatment, research, and teaching in the field of addictive behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
110.
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