全文获取类型
收费全文 | 1398篇 |
免费 | 28篇 |
专业分类
电工技术 | 15篇 |
综合类 | 2篇 |
化学工业 | 148篇 |
金属工艺 | 20篇 |
机械仪表 | 43篇 |
建筑科学 | 85篇 |
能源动力 | 29篇 |
轻工业 | 96篇 |
水利工程 | 19篇 |
石油天然气 | 2篇 |
无线电 | 107篇 |
一般工业技术 | 179篇 |
冶金工业 | 516篇 |
原子能技术 | 20篇 |
自动化技术 | 145篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2014年 | 19篇 |
2013年 | 73篇 |
2012年 | 41篇 |
2011年 | 37篇 |
2010年 | 42篇 |
2009年 | 38篇 |
2008年 | 42篇 |
2007年 | 40篇 |
2006年 | 35篇 |
2005年 | 37篇 |
2004年 | 23篇 |
2003年 | 27篇 |
2002年 | 28篇 |
2001年 | 34篇 |
2000年 | 28篇 |
1999年 | 30篇 |
1998年 | 118篇 |
1997年 | 65篇 |
1996年 | 51篇 |
1995年 | 43篇 |
1994年 | 32篇 |
1993年 | 41篇 |
1992年 | 18篇 |
1991年 | 19篇 |
1990年 | 24篇 |
1989年 | 25篇 |
1988年 | 36篇 |
1987年 | 15篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 30篇 |
1982年 | 15篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 25篇 |
1978年 | 11篇 |
1977年 | 23篇 |
1976年 | 33篇 |
1975年 | 11篇 |
1974年 | 11篇 |
1973年 | 8篇 |
1972年 | 9篇 |
排序方式: 共有1426条查询结果,搜索用时 31 毫秒
1.
Angelico Mendy Nervana Metwali Sarah S. Perry Elizabeth A. Chrischilles Kai Wang Peter S. Thorne 《Indoor air》2020,30(1):88-97
Endotoxin exacerbates asthma. We designed the Louisa Environmental Intervention Project (LEIP) and assessed its effectiveness in reducing household endotoxin and improving asthma symptoms in rural Iowa children. Asthmatic school children (N = 104 from 89 homes) of Louisa and Keokuk counties in Iowa (aged 5-14 years) were recruited and block-randomized to receive extensive (education + professional cleaning) or educational interventions. Environmental sampling collection and respiratory survey administration were done at baseline and during three follow-up visits. Mixed-model analyses were used to assess the effect of the intervention on endotoxin levels and asthma symptoms in the main analysis and of endotoxin reduction on asthma symptoms in exploratory analysis. In the extensive intervention group, dust endotoxin load was significantly reduced in post-intervention visits. The extensive compared with the educational intervention was associated with significantly decreased dust endotoxin load in farm homes and less frequent nighttime asthma symptoms. In exploratory analysis, dust endotoxin load reduction from baseline was associated with lower total asthma symptoms score (Odds ratio: 0.52, 95% confidence interval: 0.29-0.92). In conclusion, the LEIP intervention reduced household dust endotoxin and improved asthma symptoms. However, endotoxin reductions were not sustained post-intervention by residents. 相似文献
2.
3.
Emergency department status boards: user-evolved artefacts for inter- and intra-group coordination 总被引:1,自引:1,他引:0
Robert L. Wears Shawna J. Perry Stephanie Wilson Julia Galliers James Fone 《Cognition, Technology & Work》2007,9(3):163-170
Large, easily viewed status boards are commonly used in some healthcare settings such as emergency departments, operating
theaters, intensive care units, and inpatient wards. Because these artefacts were developed by front-line users, and have
little to no supervisory or regulatory control, they offer valuable insights into the theories of work and hazard held by
those users. Although the status boards case were locally developed over many years for within-group coordination, they have
also become useful for between-group coordination across organizational boundaries. In this paper, we compare and contrast
the use of such status boards in two disparate settings: a US emergency department, and a UK pediatric ward, and note striking
similarities in their form and usage, despite the large differences in setting. 相似文献
4.
5.
6.
Various indexes have been proposed to mark when a child is on the verge of acquiring new knowledge. This article described a new method for indexing this point of transition, which is based on the specificity of children's verbal explanations. The degree to which children were specific in their verbal explanations was related to whether they benefited from instruction. In particular, children who were vague in their explanations (i.e., less specific) benefited from instruction more than children who were explicit in their explanations (i.e., more specific). This index provides insights into the child's mental state prior to acquiring new knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
JR Perry SS Deodhare JM Bilbao D Murray P Muller 《Canadian Metallurgical Quarterly》1993,32(2):157-162
Sex hormones have profound effects on immune responses and may influence the outcome of autoimmune diseases such as rheumatoid arthritis (RA). We investigated the effect of gonadal steroids on the production of interleukin-1 (IL-1) and IL-6, cytokines believed to be important in the pathogenesis of RA. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy male donors and male patients with RA, and were stimulated with lipopolysaccharide (LPS) in the presence of different concentrations of 17-beta-estradiol, progesterone or testosterone. In studies of cells from normal male donors, 17-beta-estradiol at pharmacological concentrations (> or = 10(-6) M) enhanced IL-1 and IL-6 secretion as well as the production of cell-associated IL-1. Progesterone and testosterone at similar concentrations inhibited IL-1 secretion but had no significant effect on IL-6 secretion or on the production of cell-associated IL-1. In studies of male RA donors, 17-beta-estradiol failed to enhance IL-1 or IL-6 secretion and progesterone failed to inhibit IL-1 secretion. The inhibitory effects of testosterone, however, appeared to be similar to that in normal donors. It is suggested that 17-beta-estradiol may promote IL-1 and IL-6 production and release, while gestation hormone, progesterone, and testosterone may inhibit IL-1 release in vivo. These data may partly explain the gender and age differences in the incidence of RA and the development of the disease in men with low and androgen levels. 相似文献
8.
Sabha Kesraoui-Ouki Christopher R. Cheeseman Roger Perry 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(2):121-126
This paper assesses the potential of natural zeolite utilization as a low-cost ion-exchange and sorbent material in pollution control and recovery of metals. The improvement of the purity of natural zeolites coupled with their chemical modification capabilities in order to provide specific properties may provide a cost-effective alternative for the treatment of heavy metal contaminated soil and water. The application of natural zeolites in industrial pollution control is becoming important and the level of technical effort is increasingly expanding. The extent of application is unlikely to be related solely to their low cost, but also to improved properties and performance characteristics, which will advance the practical implementation of natural zeolites' technology. 相似文献
9.
The International Water Management Institute (IWMI) has made important changes in the thrust of its research programmesince 1995. These new thrusts include attention to the implications of increasing water scarcity at the global level; the adoption of a river basin paradigm leading to new insights into opportunities for water conservation and productivity; application of new information technologies and quantitative analytical techniques; and a stronger focus on policy, institutional issues, health and environment, and social inequities in access to water. This paper describes these changes and provides an overview of the remaining papers in this special issue of Water Resources Development. 相似文献
10.
J. E. Grusec and J. J. Goodnow (see record 1994-25033-001) provided a compelling framework for organizing parameters of disciplinary encounters found to affect moral internalization. However, their central hypothesis (that cognitions of accurate perception and acceptance of the message mediate the impact of specific tactics on internalization) remains untested. Before embarking on research programs designed to reveal the determinants of acceptance of parental messages in the hope that such research will inform our understanding of internalization, researchers would be well advised to devise conceptually sound measures of message acceptance and to show that message acceptance does indeed mediate internalization. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献