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   283457篇
  免费   22424篇
  国内免费   15097篇
电工技术   38672篇
技术理论   23篇
综合类   29268篇
化学工业   24772篇
金属工艺   14182篇
机械仪表   20706篇
建筑科学   27250篇
矿业工程   11700篇
能源动力   12219篇
轻工业   8366篇
水利工程   10862篇
石油天然气   11771篇
武器工业   4085篇
无线电   23779篇
一般工业技术   15321篇
冶金工业   9917篇
原子能技术   2820篇
自动化技术   55265篇
  2024年   980篇
  2023年   2806篇
  2022年   5458篇
  2021年   6838篇
  2020年   7409篇
  2019年   5442篇
  2018年   4987篇
  2017年   6847篇
  2016年   7947篇
  2015年   9069篇
  2014年   17601篇
  2013年   14982篇
  2012年   20556篇
  2011年   22073篇
  2010年   16787篇
  2009年   17009篇
  2008年   16743篇
  2007年   21225篇
  2006年   19203篇
  2005年   16996篇
  2004年   14132篇
  2003年   12687篇
  2002年   9842篇
  2001年   8362篇
  2000年   6949篇
  1999年   5445篇
  1998年   4193篇
  1997年   3420篇
  1996年   3098篇
  1995年   2592篇
  1994年   2165篇
  1993年   1497篇
  1992年   1276篇
  1991年   962篇
  1990年   742篇
  1989年   602篇
  1988年   411篇
  1987年   269篇
  1986年   184篇
  1985年   189篇
  1984年   167篇
  1983年   127篇
  1982年   122篇
  1981年   109篇
  1980年   83篇
  1979年   72篇
  1978年   60篇
  1977年   47篇
  1976年   40篇
  1959年   34篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
With the burgeoning complexity and capabilities of modern information appliances and services, user modelling is becoming an increasingly important research area. Simple user profiles already personalise many software products and consumer goods such as digital TV recorders and mobile phones. A user model should be easy to initialise, and it must adapt in the light of interaction with the user. In many cases, a large amount of training data is needed to generate a user model, and adaptation is equivalent to retraining the system. This paper briefly outlines the user modelling problem and work done at BTexact on an intelligent personal assistant (IPA) which incorporates a user profile. We go on to describe FILUM, a more flexible method of user modelling, and show its application to the telephone assistant and email assistant components of the IPA, with tests to illustrate its usefulness.  相似文献   
102.
ABSTRACT: Herring byproducts were stored at 2 and 15 °C for up to 72 h. Over time, significant increases of total volatile bases (TVB), histamine, putrescine, cadaverine, and tyramine were detected. However, only tyramine and TVB levels were temperature-dependent. The level of total polyunsaturated fatty acids (PUFAs) was constant. Longer byproducts storage gave rise to an oil with higher levels of free fatty acids, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total PUFAs, while fluorescent compounds were lower. A higher storage temperature led to oil higher in α-tocopherol and EPA levels and lower in anisidine value. Surprisingly, the oil with the highest content of PUFAs was not produced from the freshest byproducts, and oil with low oxidation products can be extracted from stored byproducts.  相似文献   
103.
蔡士杰  张福炎 《计算机学报》1991,14(10):790-797
本文介绍了一个用户接口管理系统NUUIMS的设计和实现.重点叙述了该系统基于规范化目标用户接口模型的设计思想,系统组成及描述方法.文章也讨论了使用NUUIMS设计而成的用户接口的特点.  相似文献   
104.
An iron-based amorphous foil (FeNiCrSiB) was used as an interlayer for the amorphous diffusion bonding of low carbon steel pipes under argon flux. The microstructure and mechanical properties of the joint were analyzed using an electron probe micro-analyzer (EPMA), tensile test, bending test and impact test. The results show that the joint microstructure resembles that of the base metal and no precipitates form at the joint. Melting point depressants (B, Si) diffuse far away from the joint and the base metal element is homogenous across the joint. The joint impact toughness is greater than the base metal toughness and the mechanical properties of the joint are similar around the pipe.  相似文献   
105.
介绍了韶钢6号高炉脉冲布袋除尘技术的工艺流程、主要设备、控制措施及节能效果。  相似文献   
106.
软件构件技术在管理信息系统中的应用   总被引:2,自引:1,他引:1  
软件构件技术是一种前沿的软件设计思想,其方法与传统的软件制作方法有很大区别.通过介绍软件构件技术在开发管理信息系统的应用,与其它软件制作方法进行比较,得出这样的结论:在软件编制中应用这种思想,不仅能大幅度地加快软件的开发速度,而且对整个软件行业的发展有着至关重要的推动作用。  相似文献   
107.
A general model of the response of a fluidized bed to disturbances is formulated, and the information provided by the model with respect to the dynamics of the bed, the bed plus the air-plenum and the bed plus the entire air-supply system, is investigated. Expressions given in literature on the fundamental frequency of the bed-plenum system are analyzed, and it is shown that they are a special case of the general model. In order to simulate various types of interaction between the bed and the rest of the system, experiments were performed in a cold fluidized bed unit operated under both non-circulating and circulating conditions. At low velocity, three regimes were identified: the multiple bubble regime with almost no interaction between bed and air-plenum, the single bubble regime with the interaction between bed and air-plenum only, and a regime with numerous irregular bubbles, where the bed interacted with the entire air-supply system. At high fluidization velocity, the exploding bubble regime was identified, with the same dominant frequency as that of the single bubble regime (the interaction with the air-supply system remains at that frequency). The models investigated correctly reproduce the dynamics when the bed is independent of the other parts of the system, or when the bed interacts only with the air-plenum. However, the models are only partially applicable when the bed interacts with the entire air-supply system. The reasons for this are investigated. In the case of system interaction, pressure waves, generated in the bed, interact with pressure pulsations from the air-supply system. This results in a coupled system, which is not covered by the models. Pressure waves resulting from events in the bed, are recognized as the coherent part of the cross power spectra of pressure fluctuations measured in the bed and the air-plenum.  相似文献   
108.
基于MAPINFO和VB的自来水管网信息系统的建立   总被引:2,自引:0,他引:2  
叶巧云 《地矿测绘》2003,19(1):25-26,30
介绍基于MapInfo平台,利用VB语言进行二次开发,建立自来水管网地理信息系统的关键技术及其注意的问题。  相似文献   
109.
基于AutoCAD的二次开发环境下,建立幻灯片库,在AutoCAD本身所包含的程序帮助下,将已建好的幻灯片库嵌入到AutoCAD用户专用下拉菜单中.给设计者创造属于自己的开发环境,使AutoCAD在建筑电气设计中的使用更加灵活,极大的提高设计效率.  相似文献   
110.
张仲谋教授的新著《宋词欣赏教程》,是南京大学出版社出版的“江苏省高等学校精品教材系列”中的一种。该书共8章,既构成一个严谨的教学体系,又多有创新出彩之处;对于词的艺术个性有深刻的把握和精当的阐发;又善于引导学生,循循善诱。该书既是教材,亦具有学术专著的品格。  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