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   121篇
  免费   0篇
电工技术   1篇
化学工业   9篇
金属工艺   2篇
机械仪表   1篇
建筑科学   2篇
能源动力   1篇
轻工业   3篇
无线电   3篇
一般工业技术   15篇
冶金工业   76篇
自动化技术   8篇
  2023年   1篇
  2022年   2篇
  2019年   2篇
  2017年   1篇
  2016年   1篇
  2013年   1篇
  2012年   1篇
  2011年   4篇
  2010年   4篇
  2009年   3篇
  2008年   7篇
  2007年   1篇
  2006年   11篇
  2005年   5篇
  2004年   7篇
  2003年   3篇
  2002年   9篇
  2001年   6篇
  2000年   5篇
  1999年   3篇
  1998年   5篇
  1997年   5篇
  1996年   5篇
  1995年   5篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1990年   4篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   3篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
排序方式: 共有121条查询结果,搜索用时 31 毫秒
1.
The extent to which protein synthesis is involved in working memory was investigated with the protein synthesis inhibitor anisomycin (ANI). Male albino and Long-Evans rats were trained to perform accurately on a 12-arm radial maze when delays of 240 min were interposed between Choice 6 and Choice 7. Bilateral hippocampal cannulas were then implanted. Accuracy on Choices 7–22 was studied when ANI (80 μg/μl) or saline was injected either 30 min before Choice 1 or 5–20 min after Choice 6 in Exp I. Pretrial injection of ANI significantly impaired performance following the 240-min delay, whereas ANI injected during the delay had no such effect. In Exps II and III, the ANI-induced amnesia was replicated, and the temporal course of development of the amnesia was determined. Pretrial administration of ANI did not significantly affect retention after a 2-min delay but produced amnesia after delays of 15 min or longer. Data suggest that protein synthesis is important for the formation of temporary memories, provided the retention interval is long enough. It is suggested that working memory includes both short- and long-term components. Protein synthesis appears to be important for formation of the long-term component, but not the short-term component, of working memory. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
Abstract— The main objective of this research is to develop a model of fatigue crack initiation and early crack growth in resistance spot welds that is specimen independent. This objective is achieved by examining the stress state around a resistance spot weld. A general expression for the structural stress around the weld is formulated that is dependent only on the loading immediately surrounding the weld. As such, it is specimen independent.
An additional objective is to explore the feasibility of applying this fatigue crack initiation model of life estimation using structural response data from finite element analysis (FEA). This numerical technique is often used for evaluating structural integrity of assemblies. Limited verification examples show that the structural stress range as calculated from FEA reaction load data is capable of describing fatigue crack initiation and early crack growth in cyclically loaded resistance spot welds.  相似文献   
3.
T. Jacob and K. Leonard (1986) reported that children of alcoholic fathers were comparable to children of depressed fathers in their psychosocial functioning. These results, however, were based on a relatively homogeneous sample. In the current study, previous results were extended by examining a sample of alcoholic fathers who were not screened for additional paternal psychiatric disorders or for major maternal psychopathology. Children in the unscreened and screened samples could not be distinguished in their functioning, and the majority of children of alcoholic fathers were functioning in the normal range of the Child Behavior Checklist. Given the heterogeneous adjustment in children of alcoholic fathers, the authors examined a range of factors that might protect against or exacerbate the risk associated with paternal alcoholism. Maternal depression and certain demographic characteristics were associated with poorer child functioning, particularly for male children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
4.
A series of experiments examined the abilities of infants to form categorical representations for the spatial relations above and below. Exp 1 provided evidence that 3–4 mo olds can form categorical representations for above and below when a diamond shape was presented above or below a horizontal bar. Exps 2 and 3 showed that 3- and 4-mo olds did not form categorical representations for above and below when a number of discriminably different shapes (e.g., a diamond, a triangle, a dot) appeared above or below the bar. These more abstract categorical representations for above and below were formed by 6- to 7-mo olds (Exp 4). The findings suggest an experientially or maturationally based trend, from concrete to abstract, in the categorical representation of common spatial relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
尽管模块化住宅在过去的几年中得到了极大的发展,但是对于大多数人来说它仍然是一个新概念。一位来自新英格兰传统小镇上的房主讲述自己的经历:当邻居们听说他想要搭建一套模块化住宅时,邻居们的反应非常惊讶“天哪,那将会有一辆‘拖车’停在我们这儿了!”  相似文献   
6.
An experiment is reported that examined the duration of prior processing effects in gymnastic judging. Gymnastic judges first encountered a series of gymnastic elements during a study phase. Perceptual and recognition tests then followed 1 of 3 delay conditions: immediate, 1 day, or 1 week. For perceptual judgments, gymnastic elements that were performed the same at study and test resulted in the highest level of accuracy. Elements seen for the first time were less accurate, and the lowest level of accuracy occurred for those that had changed in performance from study to test. This descending pattern of accuracy occurred for all 3 delay conditions, indicating that effects of prior processing were long lasting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
7.
The purpose of this study was to determine the extent to which refusal skills and norm setting mediated the impact of a school-based prevention program from the Alcohol Misuse Prevention Study (AMPS) on adolescent alcohol overindulgence. The AMPS is a randomized, pre-post, experimental-control study. Respondents in the present study included 6th through 10th graders (ns ranged from 232 to 371). Structural equation modeling analyses using EQS indicated that norm setting mediated the effect of the intervention on alcohol overindulgence at the 7th through the 8th grade and at the 8th through the 10th grade. In contrast, although the prevention program served to increase refusal skills, refusal skills did not mediate the effect of the program on alcohol misuse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
Behavior-state matching and synchrony in interactions were assessed in 48 depressed and nondepressed mother–infant dyads when the infants were 3 months old. Attentive/affective behavior states were coded for the infants and mothers on a negative to positive scale. The depressed mothers and their infants matched negative behavior states more often and positive behavior states less often than did the nondepressed dyads. The total percentage of time spent in matching behavior states was less for the depressed than for the nondepressed dyads. Cross-spectral analyses of the mothers' and the infants' behavior-state time series suggested only a trend for greater coherence or synchrony in the interactions of the nondepressed dyads. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
In Experiment 1 of this report, we examined the neuropharmacological nature of short-term working memory of rats trained to retrieve food from all arms of a 12-arm radial maze. Delay intervals of varying length were placed between Choices 6 and 7. Lanthanum (LaCl?) and glutamate (GLU) injected bilaterally into the hippocampus effectively impaired retention over short delay intervals, which suggests a possible role for calcium and/or potassium and for glutamate in working memory. However, another equally likely explanation for the amnesic effects of LaCl? and GLU is that these drugs impaired reference memory. To test more directly the hypothesis that LaCl?, GLU, or ANI might differentially affect working and reference memory, we tested the effects of these drugs on performance of rats trained to retrieve food from only 8 arms of the 12-arm maze in Experiment 2. The remaining 4 arms were never baited, in order to test reference memory function. We predicted that rats would make errors only in baited arms (i.e., errors of working memory). Instead, results of Experiment 2 showed that LaCl?, GLU, or ANI injection produced errors in unbaited arms even before a 120-min delay. If rats were injected with LaCl? or GLU, baited-arm errors were observed only after the delay period. No impairment of performance on baited arms were observed after injection of ANI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
This paper looks at stress intensity factors of cracks in resistance spot welded joints. Stress intensity factors have been used in the past to predict fatigue crack propagation life of resistance spot welds. However, the stress intensity factors from all previous work was based on assumed initial notch cracks at the nugget, parallel to the sheets. Physical evidence shows, however, that fatigue cracks in spot welds propagate through the thickness of the sheets rather than through the nugget. In this work, stress intensity factors of assumed notch cracks and through thickness cracks in tensile shear (TS) and modified coach peel (MCP) specimens were determined by the finite element method. The finite element results from the assumed notch cracks were compared with the results in the literature and were found to be in agreement with the results from Zhang’s equations [Int. J. Fract. 88 (1997) 167]. The stress intensity factors of assumed notch cracks were found to be different from those of through thickness cracks. To date, no analytic equations for stress intensity factors of through thickness cracks in spot welds have been published. In the current work, simple equations are proposed to estimate the KI and KII values of through thickness cracks in TS and MCP specimens.  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