全文获取类型
收费全文 | 87篇 |
免费 | 0篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 3篇 |
机械仪表 | 1篇 |
能源动力 | 1篇 |
轻工业 | 5篇 |
无线电 | 18篇 |
一般工业技术 | 13篇 |
冶金工业 | 38篇 |
原子能技术 | 2篇 |
自动化技术 | 5篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2013年 | 10篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2002年 | 2篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 31 毫秒
41.
Rotenberg L Portela LF Banks B Griep RH Fischer FM Landsbergis P 《Applied ergonomics》2008,39(5):646-652
The association between working hours and work ability was examined in a cross-sectional study of male (N=156) and female (N=1092) nurses in three public hospitals. Working hours were considered in terms of their professional and domestic hours per week and their combined impact; total work load. Logistic regression analysis showed a significant association between total work load and inadequate work ability index (WAI) for females only. Females reported a higher proportion of inadequate WAI, fewer professional work hours but longer domestic work hours. There were no significant differences in total work load by gender. The combination of professional and domestic work hours in females seemed to best explain their lower work ability. The findings suggest that investigations into female well-being need to consider their total work load. Our male sample may have lacked sufficient power to detect a relationship between working hours and work ability. 相似文献
42.
Elke Mangelsen Joachim Kilian Klaus Harter Christer Jansson Dierk Wanke Eva Sundberg 《Canadian Metallurgical Quarterly》2011,4(1)
High-temperature stress,like any abiotic stress,impairs the physiology and development of plants,including the stages of seed setting and ripening.We used the Aflymetrix 22K Barley1 GeneChip microarray to investigate the response of developing barley(Hordeum vulgare)seeds,termed caryopses,after 0.5,3,and 6 h of heat stress exposure;958 induced and 1122 repressed genes exhibited spatial and temporal expression patterns that provide a detailed insight into the caryopses'early heat stress responses.Down-regulation of genes related to storage compound biosynthesis and cell growth provides evidence for a rapid impairment of the caryopsis' development.Increased levels of sugars and amino acids were indicative for both production of compatible solutes and feedback-induced accumulation of substrates for storage compound biosynthesis.Metadata analysis identified embryo and endosperm as primary locations of heat stress responses,indicating a strong impact of short-term heat stress on central developmental functions of the caryopsis.A comparison with heat stress responses in Arabidopsis shoots and drought stress responses in barley caryopses identified both conserved and presumably heat-and caryopsis-specific stress-responsive genes.Summarized,our data provide an important basis for further investigation of gene functions in order to aid an improved heat tolerance and reduced losses of yield in barley as a model for cereal crops. 相似文献
43.
44.
45.
A technique is applied to ohtain unbiased eslimators with minimttm variance among the class of linear estimators for the standard deviation of of logistic. population with known mean. Coefficients for multiplying ordered observations are developed for complete and completc samples for n = 2(1)26. Each sample of size n is censored from above where m ≤ n. Then the smallest subset of l order slatistics from the set of m available order statistics is found which yields at list a 98.5% efficiency relative to the m-order-statistic estimator. The coefficients for the l-order-statistic estimator, the variance and efficiency relative to the estimatot, using all m order statistics are persented. 相似文献
46.
Mesoscopic level neurodynamics study the collective dynamical behavior of neural populations. Such models are becoming increasingly important in understanding large-scale brain processes. Brains exhibit aperiodic oscillations with a much more rich dynamical behavior than fixed-point and limit-cycle approximation allow. Here we present a discretized model inspired by Freeman's K-set mesoscopic level population model. We show that this version is capable of replicating the important principles of aperiodic/chaotic neurodynamics while being fast enough for use in real-time autonomous agent applications. This simplification of the K model provides many advantages not only in terms of efficiency but in simplicity and its ability to be analyzed in terms of its dynamical properties. We study the discrete version using a multilayer, highly recurrent model of the neural architecture of perceptual brain areas. We use this architecture to develop example action selection mechanisms in an autonomous agent. 相似文献
47.
Between 1988 and 1991, 644 serum samples were collected from 480 grizzly bears (Ursus arctos horribilis) and 40 black bears (Ursus americanus) from Alaska, United States of America, and were tested for selected canine viral infections and zoonoses. Antibody prevalence in grizzly bears was 0% for parvovirus, 8.3% (40/480) for distemper, 14% (68/480) for infectious hepatitis, 16.5% (79/480) for brucellosis, 19% (93/480) for tularaemia and 47% (225/478) for trichinellosis. In black bears, prevalence ranged from 0% for distemper and parvovirus to 27.5% for trichinellosis and 32% for tularaemia. Antibody prevalence for brucellosis (2.5%) and tularaemia (32%) were identical for grizzly bears and black bears from the geographical area of interior Alaska. Links between differences in prevalence and the origin of the grizzly bears were observed. Antibodies to canine distemper virus and infectious hepatitis virus were mainly detected in grizzly bears from Kodiak Island and the Alaskan Peninsula. Brucellosis antibodies were prevalent in grizzly bears from western and northern Alaska, whereas tularaemia antibodies were detected in grizzly bears from interior Alaska and the Arctic. There was a strong gradient for antibodies to Trichinella spp. from southern to northern Alaska. For most diseases, antibody prevalence increased with age. However, for several infections, no antibodies were detected in grizzly bears aged from 0 to 2 years, in contrast to the presence of those infections in black bears. Grizzly bears served as excellent sentinels for surveillance of zoonotic infections in wildlife in Alaska. 相似文献
48.
Harter James K.; Schmidt Frank L.; Hayes Theodore L. 《Canadian Metallurgical Quarterly》2002,87(2):268
Based on 7,939 business units in 36 companies, this study used meta-analysis to examine the relationship at the business-unit level between employee satisfaction-engagement and the business-unit outcomes of customer satisfaction, productivity, profit, employee turnover, and accidents. Generalizable relationships large enough to have substantial practical value were found between unit-level employee satisfaction-engagement and these business-unit outcomes. One implication is that changes in management practices that increase employee satisfaction may increase business-unit outcomes, including profit. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
49.
The relative strength of mastery motivation and need for approval was tested among 2 groups of 11-yr-olds, 40 high and 40 low scorers on the Children's Social Desirability Scale. Mastery motivation was inferred from the amount of time that Ss spent in 1 of 2 discrimination tasks, a challenging (unsolvable) or a solvable problem. To measure need for approval, Ss were tested in either a social-reinforcement or an E-absent condition. As predicted, low scorers spent more time in the unsolvable than the solvable task, with negligible condition differences. High scorers spent more time in the social-reinforcement than in the E-absent condition, with negligible task differences. On the solvable task, high Ss demonstrated poorer learning than low Ss. Sex differences revealed greater mastery motivation for boys and greater need for approval for girls. The need to study the developmental course of these motives and to investigate the antecedents of the group differences obtained is emphasized. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
50.