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   6528篇
  免费   491篇
  国内免费   300篇
电工技术   828篇
技术理论   1篇
综合类   686篇
化学工业   390篇
金属工艺   235篇
机械仪表   481篇
建筑科学   661篇
矿业工程   334篇
能源动力   255篇
轻工业   198篇
水利工程   248篇
石油天然气   499篇
武器工业   31篇
无线电   456篇
一般工业技术   262篇
冶金工业   896篇
原子能技术   51篇
自动化技术   807篇
  2024年   22篇
  2023年   58篇
  2022年   120篇
  2021年   127篇
  2020年   180篇
  2019年   125篇
  2018年   124篇
  2017年   137篇
  2016年   169篇
  2015年   210篇
  2014年   365篇
  2013年   298篇
  2012年   490篇
  2011年   559篇
  2010年   416篇
  2009年   380篇
  2008年   350篇
  2007年   450篇
  2006年   455篇
  2005年   390篇
  2004年   349篇
  2003年   332篇
  2002年   245篇
  2001年   220篇
  2000年   143篇
  1999年   117篇
  1998年   95篇
  1997年   70篇
  1996年   58篇
  1995年   48篇
  1994年   41篇
  1993年   25篇
  1992年   18篇
  1991年   11篇
  1990年   17篇
  1989年   15篇
  1988年   9篇
  1987年   5篇
  1984年   4篇
  1966年   3篇
  1965年   7篇
  1964年   6篇
  1962年   5篇
  1961年   3篇
  1960年   5篇
  1959年   9篇
  1958年   5篇
  1957年   3篇
  1956年   3篇
  1955年   7篇
排序方式: 共有7319条查询结果,搜索用时 15 毫秒
81.
Single-mother, cohabiting 2-parent, and married 2-parent families with infants were compared on maternal and infant behavior, Home Observation for Measurement of the Environment (HOME) scores, and infant's security of attachment. Married mothers and their infants demonstrated more positive behavior and received higher HOME scores when the infant was 6 and 15 months old than did their cohabiting and single counterparts. Married families were also better off than single and cohabiting families on several demographic, parent personality, financial, and social context measures. Single and cohabiting families were similar across most measures. Selection variables (maternal age, ethnic group, and education) explained much, but not all, of the family structure differences in the mother-infant relationship and the HOME. Maternal psychological adjustment, attitudes about child rearing, income, and social support explained little of the family structure variation, suggesting that characteristics that preceded marriage and conception were important determinants of family structure differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
82.
Emotional support is known to provide psychosocial benefits for women with breast cancer, but women can experience a mismatch between support that is wanted and support that is received from their personal supporter. The role of wanted and unwanted support in psychosocial adjustment was examined in 79 women recovering from breast cancer. Four distinct patterns of desired support actions were found using cluster analysis. Patterns of wanted support were not related to better or worse psychosocial adjustment. However, a misalignment of support between the provider and the receiver significantly influenced psychosocial adjustment, and unwanted but received support (support commission) was uniquely associated with poor psychosocial adjustment. Clinical interventions using the support instrument could help match support providers' actions to receivers' preferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
83.
The authors examined associations among parental and child adjustment, child syncope, somatic, and school problems. Participants were children (N = 56) ages 7-18 years with syncope. Measures included syncope severity, parental distress, and children's internalizing symptoms. For children diagnosed negative for neurocardiogenic syncope (NCS), their fathers' and their own psychological symptoms were positively associated with the severity of syncope, whereas their mothers' functioning was negatively associated with the severity of syncope. Also, for the negative NCS group, fathers' psychological functioning was associated with children's nonsyncope somatic complaints but not with their school problems. For the positive NCS group, few significant father-child associations were found, but several significant positive associations were revealed between mothers' psychological symptoms and their children's syncope as well as somatic and school problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
84.
This longitudinal study examined the relations between multiple risk indexes representing contextual adversity, income-to-needs ratios, and the elementary school adjustment of children from economically disadvantaged families. The results provide evidence for volatility in family circumstances over 2-year intervals from preschool to 5th grade, for relations between the contextual risk indexes and change in externalizing behavior, and for relations between the income-to-needs ratios and change in academic competence. The results also show differences in the timing of the effects. Little evidence was found for persistence effects. Theoretical implications concern conceptualizations of the diverse and dynamic nature of the family circumstances experienced by disadvantaged children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
85.
Format dependence implies that assessment of the same subjective probability distribution produces different conclusions about over- or underconfidence depending on the assessment format. In 2 experiments, the authors demonstrate that the overconfidence bias that occurs when participants produce intervals for an uncertain quantity is almost abolished when they evaluate the probability that the same intervals include the quantity. The authors successfully apply a method for adaptive adjustment of probability intervals as a debiasing tool and discuss a tentative explanation in terms of a naive sampling model. According to this view, people report their experiences accurately, but they are naive in that they treat both sample proportion and sample dispersion as unbiased estimators, yielding small bias in probability evaluation but strong bias in interval production. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
86.
Two expanded models (i.e., mediated and moderated) of the theory of work adjustment (TWA; R. V. Dawis, G. England, & L. H. Lofquist, 1964; R. V. Dawis & L. H. Lofquist, 1984) were tested for their capacity to explain the job satisfaction of a sample of lesbian, gay, and bisexual employees (N=397). Consistent with cultural critiques of the TWA, person-organization fit perceptions were tested as the mediator of the relationship between heterosexism and job satisfaction in one set of hypotheses, and experiences with informal heterosexism were tested as a moderator in the relationship between person-organization fit perceptions and job satisfaction in a separate set of hypotheses. The mediated model but not the moderated model was supported. Results were confirmed by a cross-validation sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
87.
针对JNX70-2型大容积焦炉炉头倒焦问题进行了分析,提出了改进措施。在保证焦炭质量的前提下通过调整标准温度、调节焦炉煤气掺混比、优化边火道温度等措施,成功解决了炉头倒焦现象,降低了劳动强度,确保了设备稳定运行。  相似文献   
88.
讨论了上海光源(SSRF)XAFS光束线高次谐波抑制镜箱的研制.高次谐波抑制镜箱为XAFS实验提供高纯度光谱,主要机械结构包括镜子夹持机构、平移切换机构、三点调整机构.在机构设计中进行了分析与计算.根据测试获得的摇摆曲线对高次谐波抑制镜箱性能进行评估.  相似文献   
89.
本文介绍了SLMOREG K 6RA24全数字直流调速系统参数最优化的调整过程。  相似文献   
90.
廖旭志 《宽厚板》2004,10(4):30-33
本文论述了西门子6RA70装置在双边剪夹送辊传动系统中的应用,解决了夹送辊不同步而出现的钢板走偏问题。  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