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   670704篇
  免费   7634篇
  国内免费   1407篇
电工技术   11713篇
综合类   2774篇
化学工业   102823篇
金属工艺   30991篇
机械仪表   23596篇
建筑科学   15056篇
矿业工程   5110篇
能源动力   15842篇
轻工业   49225篇
水利工程   8394篇
石油天然气   15701篇
武器工业   39篇
无线电   71260篇
一般工业技术   138551篇
冶金工业   100125篇
原子能技术   15171篇
自动化技术   73374篇
  2021年   5506篇
  2019年   5279篇
  2018年   25086篇
  2017年   24423篇
  2016年   20460篇
  2015年   6744篇
  2014年   10495篇
  2013年   26339篇
  2012年   19466篇
  2011年   32592篇
  2010年   27356篇
  2009年   26578篇
  2008年   27821篇
  2007年   29341篇
  2006年   16437篇
  2005年   17458篇
  2004年   15958篇
  2003年   15619篇
  2002年   14101篇
  2001年   12991篇
  2000年   12578篇
  1999年   12093篇
  1998年   27731篇
  1997年   20088篇
  1996年   15693篇
  1995年   12054篇
  1994年   10906篇
  1993年   10661篇
  1992年   8368篇
  1991年   8154篇
  1990年   7999篇
  1989年   7773篇
  1988年   7496篇
  1987年   6762篇
  1986年   6549篇
  1985年   7417篇
  1984年   6720篇
  1983年   6457篇
  1982年   5795篇
  1981年   5912篇
  1980年   5644篇
  1979年   5740篇
  1978年   5671篇
  1977年   6189篇
  1976年   7697篇
  1975年   5116篇
  1974年   4914篇
  1973年   4986篇
  1972年   4283篇
  1971年   4041篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
At times, people keep their emotions from showing during social interactions. The authors' analysis suggests that such expressive suppression should disrupt communication and increase stress levels. To test this hypothesis, the authors conducted 2 studies in which unacquainted pairs of women discussed an upsetting topic. In Study 1, one member of each pair was randomly assigned to (a) suppress her emotional behavior, (b) respond naturally, or (c) cognitively reappraise in a way that reduced emotional responding. Suppression alone disrupted communication and magnified blood pressure responses in the suppressors' partners. In Study 2, suppression had a negative impact on the regulators' emotional experience and increased blood pressure in both regulators and their partners. Suppression also reduced rapport and inhibited relationship formation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
992.
This research reports age and gender differences in cardiac reactivity and subjective responses to the induction of autobiographical memories related to anger, fear, sadness, and happiness. Heart rate (HR) and subjective state were assessed at baseline and after the induction of each emotion in 113 individuals (61 men, 52 women; 66% European American, 34% African American) ranging in age from 15 to 88 years (M = 50.0; SD = 20.2). Cardiac reactivity was lower in older individuals; however, for anger and fear, these age effects were significantly more pronounced for the women than the men. There were no gender differences in subjective responses, however, suggesting that the lower cardiac reactivity found among older people is dependent on gender and the specific emotion assessed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
993.
This study evaluated relations among optimism, perceived stress management skills (PSMS), and positive mood in 46 men who had surgical treatment for localized prostate cancer. The authors found that optimism, PSMS, and positive mood scores were positively correlated. Positive mood was unrelated to demographic and disease-related control variables. In a hierarchical regression model controlling for PSMS, the relationship between optimism and positive mood became nonsignificant, whereas PSMS remained a correlate of positive mood. Results suggest that the relationship between optimism and positive mood may be mediated by belief in being able to use stress management techniques effectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
994.
A process of physical refining wheat germ oil using the technique of molecular distillation (MD) is presented in this work. Wheat germ oil was obtained from the germ by solvent extraction using hexane and also by cold pressing. The oil extracted with hexane was degummed and bleached before deacidification in order to modify the parameters of phosphorus and color. The goal in carrying out the stage of physical refining by MD was to preserve the maximum amount of original antioxidative potential obtained from extraction of the crude oil. The effect of evaporation temperature of one‐stage MD on the efficiency of free fatty acid elimination was studied. The antioxidant portion was followed by means of analytic determination of tocopherols by high‐performance liquid chromatography. Tocopherol retention up to 98% was achieved in the oil extracted by pressing, and yields of up to 96% were achieved in the oil extracted with hexane. Copyright © 2007 Society of Chemical Industry  相似文献   
995.
A range of refractories is presented for handling steel outside a furnace, which are produced by the Borovichi Refractories Corporation. The refractory characteristics and working features are given. Translated from Novye Ogneupory, No. 9, pp. 29–35, September, 2008.  相似文献   
996.
Production methods used to prepare graphite crucibles with high operating properties are considered: use as a filler of good graphitizing acicular coke, vibration molding of the original coke mix, use of production cycles for impregnation with medium temperature coal-tar pitch — firing, firing of compacted billets in metal containers, graphitization of fired billets in graphite cylinders. The last two production methods make it possible to reduce the temperature drop throughout the volume of a billet during heat treatment, and as a consequence to reduce crack development to a minimum as a result of reducing thermal stresses. All of the production methods recommended may be entirely accomplished in existing electrode plants and may be used to increase markedly the quality crucible graphite. It is possible to achieve a quality for these materials at the best world level. Translated from Novye Ogneupory, No. 8, pp. 28–33, August 2008.  相似文献   
997.
Research results are given on magnesian box-type components in the tuyere belt of horizontal converters at Ufalei Nickel Corporation. The purpose has been to eliminate the zoning in them by impregnation with nickel or copper mattes to relieve thermal stresses during use. Components impregnated with matte show improved physicomechanical and thermophysical properties. A technology has been developed and tested for impregnating standard components under conditions found at Ufalei Nickel Corporation. Translated from Novye Ogneupory, No. 5, pp. 44–47, May, 2008.  相似文献   
998.
Technology is developed for preparing refractory components made of partially stabilized zirconium dioxide using an isostatic compaction press. Technology is provided for manufacturing dispensing nozzles using combined and separately stabilized zirconium dioxide, and also indices of the refractories obtained and imported materials are compared. __________ Translated from Novye Ogneupory, No. 3, pp. 127–131, March 2008.  相似文献   
999.
Compositions have been developed for nonshrinking vibrocast thermally insulating light refractory concretes with densities of 1.0, 1.3, 1.5, and 1.8 g/cm3 for temperatures of use up to 1400°C. The structure and properties have been examined for the concrete of density 1.3 g/cm3. __________ Translated from Novye Ogneupory, No. 4, pp. 29–32, April, 2008.  相似文献   
1000.
Secondary aluminum waste products, and processes that occur during heating and mineral formation on introducing fine periclase powder into the composition of waste products are studied. It is demonstrated that secondary aluminum production waste may be used as a raw material for synthesizing aluminomagnesia spinels. Translated from Novye Ogneupory, No. 6, pp. 15–18, June 2008.  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