全文获取类型
收费全文 | 1064篇 |
免费 | 116篇 |
国内免费 | 66篇 |
专业分类
电工技术 | 45篇 |
技术理论 | 1篇 |
综合类 | 212篇 |
化学工业 | 58篇 |
金属工艺 | 50篇 |
机械仪表 | 54篇 |
建筑科学 | 166篇 |
矿业工程 | 49篇 |
能源动力 | 16篇 |
轻工业 | 86篇 |
水利工程 | 27篇 |
石油天然气 | 62篇 |
武器工业 | 8篇 |
无线电 | 60篇 |
一般工业技术 | 83篇 |
冶金工业 | 124篇 |
原子能技术 | 6篇 |
自动化技术 | 139篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 16篇 |
2021年 | 22篇 |
2020年 | 15篇 |
2019年 | 22篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 24篇 |
2015年 | 30篇 |
2014年 | 68篇 |
2013年 | 45篇 |
2012年 | 81篇 |
2011年 | 90篇 |
2010年 | 79篇 |
2009年 | 63篇 |
2008年 | 63篇 |
2007年 | 90篇 |
2006年 | 104篇 |
2005年 | 82篇 |
2004年 | 58篇 |
2003年 | 50篇 |
2002年 | 44篇 |
2001年 | 31篇 |
2000年 | 30篇 |
1999年 | 16篇 |
1998年 | 8篇 |
1997年 | 11篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1985年 | 1篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 2篇 |
1958年 | 1篇 |
1956年 | 2篇 |
1955年 | 4篇 |
1954年 | 2篇 |
排序方式: 共有1246条查询结果,搜索用时 156 毫秒
101.
升空平台雷达信息传输系统的设计实现 总被引:1,自引:0,他引:1
升空平台雷达信息传输系统是将安装在空中平台上的雷达探测设备的信息下传回地面终端,同时将地面对空中雷达的控制命令上传至空中平台上的雷达设备。介绍了升空平台雷达信息传输系统的设计,对系统工作原理、雷达原始视频、监控图像的下传和地面对空中平台上雷达设备的控制模块进行了阐述。 相似文献
102.
103.
In rat selectively bred for different amygdala kindling rates (Fast vs. Slow), comorbid differences in learning were detected. Here, performance was tested in a delayed alternation task before, during, and after kindling. Although similar reference memory was evident, Fast rats showed working memory deficits with increasing delays between information and choice trials. Further, seizures shortly before learning disrupted both reference and working memory in Fast, but not Slow, rats. Weeks after kindling, progressive delays further disrupted Fast rats, but only longer delays disrupted Slow rats. Clearly relevant to individual differences in human epilepsy, a temporal lobe, seizure-prone genetic background in rats provides poorer original learning and easier disruption of new learning by recent and past seizures than a seizure-resistant background. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
苏平 《重庆理工大学学报(自然科学版)》2007,21(2):94-98,123
对国际公约(协议、法律)语境中地理标志相关法律术语和我国法律(法规)语境中有关地理标志相关术语进行考辨;分析了来源地标识、地理标志、原产地名称三者的关系;指出我国有关原产地标记、地理标志等术语的认识有一个从混淆到厘清的过程。 相似文献
105.
This article discusses the Stanford-Binet, Fourth Edition (1986). Psychologists using it for the first time may be surprised to discover that the test resembles a new test more than a revision of the old instrument. Differences between this edition and earlier versions are noted. For example, reliance on age levels is gone from the new test. Other changes in test format are discussed. Also noted are problems the test presents for the examiner. For example, instructions and scoring guidelines are sometimes inadequate. The article reviews the adequacy of the technical manual, standardization of the test, the internal consistency reliability of this Fourth Edition, and its validity. The reviewers suggest that practitioners may wish to become well-acquainted with the new Stanford-Binet so that its use might be an option for them, but they should not give the test a superior rating just because of its name. Given the hefty cost of the instrument and the time needed to master it, potential users with limited budgets and limited time may well find that their evaluation needs can be adequately filled by using another test of cognitive ability already in their possession. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
王桂杰 《沈阳化工学院学报》1995,9(2):101-108
用超平同法对2m阶常微分方程二点边界值问题进行探讨,在已知m个初始条件下确定另外m个未知初始值的方法。 相似文献
107.
ZD-MCADⅡ是一个面向机械产品的特征造型系统,它结合了传统造型与特征造型的功能,同时也结合了特征识别与提取的功能。本文对本系统的功能及体系结构作了较为详细的介绍,并着重讨论了基于空间约束的特征编辑与特征库的实现方案。其原型系统已完成 相似文献
108.
Comments on how few authors of APA journal articles retain their original data. Some authors have suggested that the APA journals take steps to insure that authors store their data for future reference. The commentator provides specific reasons for the retention of original data. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
In an analysis of the content of ten recently published textbooks in psychology, the author concludes that most textbooks contain the implication that psychologists are male by using language and illustrations reinforcing this suggestion, and by citing women authors less frequently than their number and eminence would suggest. Experiments and studies reported in psychology textbooks frequently fail to indicate sex of subjects or, alternatively, are based on male samples. The results of such studies are then frequently generalized to both sexes. The image of psychology as presented in textbooks is biased, therefore, toward the study of male behaviour by male psychologists. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
110.
The rectangular influence graph (RIG) is presented as an extension of the relative neighborhood graph (RNG). The RNG is an efficient tool for analyzing the clustering of multidimensional feature vectors when all the features are quantitative. The RIG is a similar tool that can accommodate feature vectors some of whose components are qualitative. We show that the RIG is a superset of the Gabriel graph with respect to any Minkowski metric.As tools to analyze interclass structure, the interclass RIG (IRIG) and the mutual neighborhood graph (MNG) are presented. These graphs can be used to reduce the training set in the design of piecewise linear classifiers. The MNG leads also to a sufficient condition for the linear separability between classes. 相似文献