全文获取类型
收费全文 | 1359篇 |
免费 | 16篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 40篇 |
机械仪表 | 5篇 |
建筑科学 | 11篇 |
能源动力 | 3篇 |
轻工业 | 31篇 |
水利工程 | 10篇 |
无线电 | 26篇 |
一般工业技术 | 46篇 |
冶金工业 | 1187篇 |
自动化技术 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 3篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 11篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 7篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 35篇 |
1998年 | 391篇 |
1997年 | 199篇 |
1996年 | 116篇 |
1995年 | 81篇 |
1994年 | 61篇 |
1993年 | 79篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 13篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 17篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 1篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 13篇 |
1977年 | 34篇 |
1976年 | 56篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1377条查询结果,搜索用时 156 毫秒
71.
72.
The study was conducted in 55 patients with cardiac pains. Electrocardiography was used successively prior to, during and following physical exercises, followed by Seldinger selective coronary angiography, and electrocardiography prior to, during and following hyperventilation tests. In 2 of 55 patients the result of the exercise test was interpreted as false-positive, since the coronary angiography demonstrated intact vessels, and during hyperventilation ECG recorded a decreased ST segment. To avoid false-positive results in patients with suspected angina pectoris the physical exercises tests can be considered positive only in cases in which hyperventilation caused no ECG changes typical for angina pectoris. 相似文献
73.
This study explored the relationship of cognitively induced anxiety and hand temperature reduction in a nonclinical sample. Forty college students were randomly assigned to either the Anxiety Group or the Pleasant Group. Following a baseline period, individuals in the Anxiety Group discussed with the experimenter topics which were anxiety-producing for them. Individuals in the Pleasant Group discussed topics of a pleasant nature. During these discussions, hand temperatures were recorded from the palmar surface of the third finger on the dominant hand. Data analysis indicated that hand temperature decreases were significant only in subjects discussing anxiety-producing topics. 相似文献
74.
75.
76.
This paper considers a two unit cold standby redundant system subject to a single repair facility with exponential failure and general repair time distribution. Each unit can work in three different modes — normal, partial failure and total failure. There is a perfect switch to operate the standby unit on total failure of the operative unit. The system has been analysed to determine the reliability parameters e.g. mean time to system failure (MTSF), steady state availability, mean recurrence to a state and expected number of visits to a state, first two moments of time in transient state, by using the theory of Semi-Markov Process. Howard's reward structure has been super-imposed on the Semi-Markov Process to obtained expected profit of the system. A number of results obtained earlier are derived as particular cases. 相似文献
77.
78.
The daily dietary intakes and total contents of Cs and I in skeletal muscle and thyroid, respectively, for an average Indian adult were estimated by determining their concentrations in the total cooked diet and tissue samples using instrumental neutron activation analysis. These data were then used to predict the biological half-lives of Cs and I and their radioactive counterparts for the Reference Indian Man. The predicted biological half-lives of Cs and I for Reference Indian Man were found to be comparable with the reported values for the ICRP Reference Man. 相似文献
79.
Tilke A. T. Stapelmann C. Eller M. Bach K.-H. Hampp R. Lindsay R. Conti R. Wille W. Jaiswal R. Galiano M. Jain A. 《Semiconductor Manufacturing, IEEE Transactions on》2007,20(2):59-67
In the present work, a high aspect ratio process (HARP) using a new O3/TEOS based sub atmospheric chemical vapor deposition process was implemented as STI gapfill in sub-65-nm CMOS. Good gapfill performance up to aspect ratios greater than 10:1 was demonstrated. Since the HARP process does not attack the STI liner as compared to HDP, a variety of different STI liners can be implemented. By comparing HARP with HDP, the geometry dependence of nand p-FET performance due to STI stress is discussed 相似文献
80.